Kratom Lab Calibration Explained: Reference Standards, Curves and Quality Controls

The short answer

A laboratory instrument does not read a kratom sample and
automatically know that it contains a particular percentage of
mitragynine or a particular number of milligrams of 7-OH. The instrument
produces a response—often a chromatographic peak and associated detector
signal. The laboratory must connect that response to known reference
values through a documented calibration system.

That system commonly includes:

1. a properly identified reference standard;
2. a documented purity or assigned-value correction;
3. accurately prepared stock and working solutions;
4. a calibration range appropriate for the expected sample
   concentration;
5. blanks, calibration standards and quality-control materials;
6. an accepted mathematical model;
7. checks for instrument performance, carryover and drift;
8. validated or verified sample preparation for the relevant product
   matrix; and
9. independent review of calculations, units, dilutions and
   results.

A polished certificate of analysis does not reveal all of this
evidence. It normally reports the result, method and selected sample
details. That is why a buyer should not treat a laboratory logo, an
r² value or the phrase “LC-MS/MS tested” as a complete
demonstration of accuracy.

Calibration is one link in the evidence chain. It cannot fix a
mislabeled sample, an unrepresentative sampling plan, poor extraction
recovery, a matrix effect, an incorrectly entered dilution or a report
attached to the wrong lot.

What calibration
means in alkaloid testing

In quantitative chemical testing, calibration establishes the
relationship between known analyte amounts and measured instrument
responses. A laboratory may prepare several solutions containing known
concentrations of mitragynine, 7-OH or another target. The instrument
measures each solution. Software then fits a mathematical relationship
between concentration and response.

The laboratory uses that relationship to estimate the concentration
in an unknown sample—but only after the sample has been weighed or
measured, extracted, diluted, analyzed and evaluated under the method’s
rules.

The basic logic is:

known standard concentrations → measured responses → calibration model → unknown response → calculated extract concentration → dilution and sample-weight corrections → reported product result

Each arrow can introduce error. A sound laboratory controls and
documents those transitions.

The National Institute of Standards and Technology supports
comparable measurements by producing Standard Reference Materials with
well-characterized composition or properties. FDA’s chemical-method
validation guidance defines a reference material as sufficiently
homogeneous and stable for an intended measurement use and describes a
reference standard as a high-metrological-quality standard from which
measurements are made or derived.

Those definitions matter because “standard” can mean different things
in casual marketing. A bottle from a chemical supplier is not
automatically a NIST Standard Reference Material. A vendor’s stated
purity is not automatically a certified value. A laboratory should know
what kind of material it has, what value it is using and how that value
is traceable.

Calibration
is not the same as instrument maintenance

Several activities are often compressed into the phrase “the machine
is calibrated.” They answer different questions.

Activity	Main question	Example
Instrument qualification	Is the instrument installed and operating as intended?	Pump flow, detector response, mass accuracy or temperature checks
Equipment calibration	Does a measuring device agree with an appropriate reference?	Balance weights, pipette volume or thermometer comparison
Analytical calibration	What relationship links analyte concentration to detector response?	A multi-level mitragynine calibration curve
System suitability	Is the analytical system performing adequately for this run?	Retention, response, peak shape, resolution or repeatability checks
Method validation	Can the procedure perform adequately for its intended use?	Accuracy, precision, specificity, range and sensitivity studies
Method verification	Can this laboratory perform an established procedure adequately?	Local performance checks with its analysts, equipment and matrix
Quality control	Did this particular batch remain under control?	Blanks, fortified samples, controls, duplicates and continuing checks

A current balance calibration does not prove the alkaloid method is
accurate. A passing calibration curve does not prove sample extraction
was complete. A validated method does not prove that every later run was
acceptable. These controls support one another; they are not
interchangeable.

The
measurement chain from reference material to COA

1. Identify the analyte
precisely

The laboratory must define what it intends to measure. “Kratom
alkaloids” is too broad for a quantitative claim. Mitragynine and
7-hydroxymitragynine are distinct analytes. Other alkaloids and
manufactured derivatives may require separate standards, chromatographic
separation and detection criteria.

Names alone may also be inadequate. The reference-standard record
should include a chemical identity, relevant form and identifying
information supplied by the producer. The method should address the
possibility of structurally related compounds, isomers or co-eluting
peaks when those could affect the result.

This becomes especially important for 7-OH, mitragynine pseudoindoxyl
(MGPI), MGM-15 and MGM-16. These names should not be used as though they
describe one interchangeable substance. As of September 3, 2026, the
federal 7-OH threshold remains the subject of a pending proceeding,
while MGPI, MGM-15 and MGM-16 are separately in federal Schedule I under
a temporary order effective August 26, 2026. A test panel and COA should
identify which substances were actually within the method’s scope.

2. Establish
the reference standard’s assigned value

A reference standard may have a labeled purity, mass fraction,
concentration or other assigned value. The laboratory should retain the
current certificate and understand whether the value is:

• certified or informational;
• stated on an as-is or dried basis;
• corrected for water, residual solvent or inorganic content;
• expressed for a free base, salt or another chemical form;
• accompanied by uncertainty;
• valid only under specified storage and handling conditions; and
• subject to an expiration or requalification date.

Using “100%” in a calculation when the certificate assigns 94.7% can
bias every standard prepared from that material. Using a salt mass as
though it were the free compound can also produce a systematic error.
The exact correction depends on the material and certificate; it should
not be guessed.

3. Prepare the primary
stock solution

The laboratory weighs or otherwise measures the reference material
and brings it to a defined volume or mass using a suitable solvent.
Records should identify:

• standard producer and catalog number;
• standard lot;
• certificate version;
• assigned value and correction used;
• balance and volumetric equipment;
• actual mass weighed;
• solvent identity and lot;
• final volume or mass;
• calculated concentration;
• preparer and verifier;
• preparation date;
• storage condition; and
• expiration or use-by determination.

Transcription matters. A misplaced decimal at this stage can pass
invisibly through every working solution and every result if there is no
independent check.

4. Prepare working standards

The primary stock may be too concentrated for direct use. The
laboratory prepares one or more intermediate and working solutions by
controlled dilution. Each step needs traceable calculations and suitable
volumetric equipment.

Serial dilution can amplify an error: if the first intermediate is
wrong, every later calibrator made from it may be wrong in the same
direction. Independent preparation of a quality-control solution—ideally
from a separate stock and, when feasible, a different standard lot or
source—can help detect this shared error.

5. Build the calibration
standards

Calibration standards span the working range of the method. The
method should define:

• the number and nominal concentrations of levels;
• whether standards are solvent-based or matrix-matched;
• whether a blank and internal-standard-only zero are used;
• preparation sequence;
• replicate requirements;
• acceptance criteria for individual points;
• regression model and weighting;
• rules for excluding a failed level; and
• the lower and upper reportable boundaries.

There is no single universal curve design for every kratom analyte,
matrix and instrument. A curve suitable for a plain-leaf mitragynine
assay may be unsuitable for trace 7-OH measurement or a highly
concentrated extract.

6.
Analyze controls that do not merely repeat the curve

Quality-control samples should challenge the measurement process
rather than simply echo it. Depending on the method, these may
include:

• reagent blanks;
• method blanks;
• matrix blanks;
• fortified matrix samples;
• laboratory-control samples;
• low-, middle- and high-level controls;
• duplicate preparations;
• continuing calibration checks;
• carryover blanks;
• internal-standard response checks; and
• retained control materials used for trend monitoring.

If every calibrator and control comes from the same incorrectly
prepared stock, they may agree with one another while remaining wrong.
Independence in preparation can reveal errors that curve statistics
cannot.

7. Process the unknown sample

The laboratory weighs a test portion, extracts the analyte, performs
any cleanup or concentration step, dilutes the extract and introduces it
to the instrument. The final COA value may include several factors:

instrument result × extract volume × dilution factors × purity or basis corrections ÷ sample amount

The method may also apply recovery, moisture or density information
when scientifically justified. Each factor needs the correct units. A
defensible raw-data package should make the calculation
reproducible.

Reference
standard, certified reference material and internal standard

These terms are related but not identical.

Reference material

A reference material has properties established well enough for an
intended measurement or examination use. Its fitness depends on the
question. A material useful for checking botanical identity may not be
appropriate for assigning an exact alkaloid concentration.

Certified reference material

A certified reference material comes with documentation assigning one
or more property values through technically valid procedures, generally
with uncertainty and traceability information. “Certified” should point
to the actual certificate and producer—not merely appear as an
unsupported adjective.

NIST’s trademarked Standard Reference Materials are one category of
highly characterized materials. NIST does not offer an SRM for every
analyte or every botanical matrix. The absence of a NIST-branded kratom
standard does not by itself make analysis impossible, but it increases
the importance of supplier qualification, characterization, traceability
and fit-for-purpose evaluation.

Primary and secondary
standards

A primary reference standard is the high-level comparison material on
which other standards are based. A secondary or working standard may be
qualified against it for routine use. FDA’s laboratory-control Q&A
explains, in the pharmaceutical CGMP context, that a new batch of highly
pure reference material should be qualified against the primary
reference standard when used for system suitability.

Kratom testing laboratories should not claim that drug CGMP
requirements automatically govern every botanical product. The principle
is still instructive: a replacement standard should not quietly enter
service without documented comparison and approval.

Internal standard

An internal standard is added at a controlled amount to standards,
controls and samples. It can help account for variation in injection,
sample preparation or detector response. In mass-spectrometric methods,
a stable-isotope-labeled analogue may behave similarly to the target
while remaining distinguishable by mass.

An internal standard is not the analyte calibration standard. It does
not prove that the target identity is correct or that the sample matrix
has no effect. Its usefulness depends on when it is added, how closely
it tracks the analyte and whether the method has demonstrated adequate
performance.

Why purity, form and
stability matter

Purity corrections

Suppose a laboratory weighs 10.00 mg of a reference material assigned
96.0% purity and prepares 10.00 mL of solution. Ignoring all other
corrections, the analyte amount is 9.60 mg, not 10.00 mg. The nominal
concentration would be 0.960 mg/mL rather than 1.000 mg/mL.

That 4% difference can affect every sample result calculated from the
stock. The example is intentionally simple; an actual certificate may
require additional interpretation.

Chemical form

The molecular mass and analyte fraction can differ between a free
compound and a salt or solvate. The laboratory should use the form
described on the certificate and method. It should not substitute a
differently characterized material solely because the common name looks
similar.

Stability

Reference solutions can change through light, heat, oxidation,
evaporation, adsorption, contamination or repeated freeze-thaw cycles.
The procedure should define storage, container type, allowed exposure
and use period. An expiration date copied from a supplier’s unopened
container does not automatically establish the life of a
laboratory-prepared solution.

The standard log should capture receipt, opening, preparation and
disposal. If a stability period is assigned to a stock or working
solution, the laboratory should have supporting evidence or a defensible
source—not just a recurring calendar habit.

Reading a
calibration curve without being misled

Range

The calibration range is the interval over which the method has
demonstrated acceptable quantitative performance. An unknown above the
upper limit should generally be diluted and reanalyzed under validated
dilution rules. A result below the lower quantitative limit should not
be transformed into a precise number merely by extending the curve
mathematically.

This matters when one method is used for several product types. Plain
leaf, extract and concentrated 7-OH can differ greatly in analyte
concentration. A laboratory may need different dilution schemes or
ranges.

Model

The relationship between concentration and response may be linear or,
when justified, another form. Software can fit many equations. The fact
that a model produces a curve does not show that it is appropriate.

The laboratory should predefine or scientifically justify:

• model type;
• weighting, such as equal, 1/x or 1/x²
  weighting;
• allowed point exclusions;
• back-calculated accuracy criteria;
• residual review; and
• batch-acceptance rules.

Changing the model after seeing which option makes an unknown sample
pass a specification is not sound practice.

Why r² is not enough

The coefficient of determination can describe how closely data fit a
model, but it does not independently establish accuracy throughout the
range. A curve can show a visually impressive r² while a
low-level standard has substantial bias, weighting is unsuitable or the
range is too broad.

A useful review considers back-calculated standard results, residual
patterns, low-end performance, control recoveries and predefined
criteria. There is no universal r² threshold that proves
every kratom assay is valid.

Blanks and zero samples

A reagent or solvent blank can reveal contamination or carryover from
the analytical system. A method blank passes through sample preparation
and can reveal contamination introduced by reagents, containers or the
process. A matrix blank contains a comparable matrix without the target
when such material is available.

In methods using an internal standard, a “zero” sample may contain
internal standard but no target analyte. The laboratory should use each
blank for its defined purpose. “Blank passed” is incomplete if the
record does not identify which kind of blank and what criterion
applied.

Continuing calibration
checks

Instrument response may drift after the initial curve. Continuing
checks can be inserted through a batch to show that performance remains
acceptable. A passing opening curve does not guarantee that the system
remained stable for the final samples.

The sequence should also address carryover. A high-concentration
extract injected immediately before a low-level botanical sample could
affect the next result if the system is not adequately washed and
checked.

Matrix
effects: why clean standards are not the whole answer

Kratom powder is a complex botanical matrix. Pigments, other
alkaloids, plant compounds and extraction residues can affect recovery,
chromatography or ionization. Capsules introduce shell material;
flavored products introduce additional ingredients; liquids may contain
sweeteners, acids, preservatives or emulsifiers.

A standard prepared in clean solvent does not experience all of those
effects. The method may address matrix influence through:

• matrix-matched calibration;
• stable-isotope internal standards;
• standard addition;
• sample cleanup;
• dilution;
• fortified recovery experiments;
• comparison across product matrices; or
• another validated strategy.

No single technique is automatically best in every case. The
laboratory should demonstrate that its chosen approach works for the
matrix being reported.

FDA’s chemical-method validation guidance specifically treats matrix
as a method-performance factor. It notes that a new matrix may require
verification or extension work and that matrix-matched calibration or
isotopically labeled internal standards can affect the design of those
studies.

Calling a product “kratom” does not make all kratom products one
matrix. A method verified only for plain powder should not be assumed to
perform identically for gummies, syrup, multi-ingredient beverages or
highly concentrated extracts.

System
suitability is the gate before sample interpretation

System-suitability checks ask whether the instrument and analytical
system are capable of acceptable performance at the time of use.
Depending on the method, the checks may evaluate:

• retention-time consistency;
• peak-area or height repeatability;
• signal-to-noise;
• chromatographic resolution;
• peak shape;
• mass accuracy;
• ion ratios;
• internal-standard response; or
• carryover.

FDA’s current laboratory-control Q&A states that system
suitability should use qualified primary or secondary reference
standards and suitable materials. It also distinguishes an appropriate
standard injection from an unofficial “trial injection” of a product
sample.

A COA usually does not list every suitability result. Buyers can
still ask whether the method defines suitability, whether the run passed
and whether failures are retained and investigated rather than
erased.

Quality
controls should be capable of catching mistakes

Good controls are selected to detect likely failure modes.

Possible failure	Control that may help reveal it
Contaminated solvent or vial	Reagent or solvent blank
Contamination during extraction	Method blank
Poor extraction recovery	Fortified matrix sample
Curve-stock preparation error	Independently prepared QC stock
Injection or detector variability	Internal standard and repeatability check
Instrument drift	Continuing calibration verification
Carryover after a high sample	Blank placed after the high sample
Nonuniform product or subsampling	Independent sample preparations or duplicates
Matrix suppression or enhancement	Matrix comparison, spike recovery or suitable internal standard
Dilution outside validated behavior	Dilution-integrity control

Running more controls is not automatically better if none target the
relevant risk. The laboratory should define what each control means,
where it appears in the sequence and what happens if it fails.

Controls should not be used to cosmetically “correct” a failing batch
after the fact. A failed control calls for a documented assessment under
the laboratory’s procedure. Repeated reinjection, unexplained point
deletion or selective reporting can hide an unstable system.

Product form
changes the calibration challenge

Product type	Main analytical concern	Calibration or QC implication
Whole or cut leaf	Nonuniform material and extraction	Representative milling or subsampling and demonstrated recovery
Plain powder	Matrix load and lot variability	Matrix performance across relevant leaf lots
Pure-leaf capsules	Shell contribution and fill variation	Defined treatment of shell and representative capsule sampling; Kiody capsules are approximately 500 mg of pure leaf, not extract
Extract powder	High analyte concentration	Validated dilution and protection against detector saturation
Liquid extract	Density, volume basis and phase behavior	Homogenization instructions, density or volume records and compatible range
Enhanced leaf	Added material may be nonuniform	Multiple preparations, blend-uniformity evidence and carryover controls
Multi-ingredient edible or beverage	Complex matrix and serving conversions	Matrix-specific recovery plus correct per-unit calculations
Concentrated 7-OH	High level, legal thresholds and carryover	Separate range, identity confirmation, contamination control and precise basis reporting
MGPI, MGM-15 or MGM-16	Controlled-substance status	Appropriate federal authorization for handling and analyte-specific scope; Kiody does not sell these substances

The instrument name does not solve these differences. LC-MS/MS may be
highly selective and sensitive, but the method still requires suitable
extraction, standards, range, controls and data review.

Calculations
that commonly separate a good result from a bad one

Dilution factors

If 1.00 mL of an extract is diluted to 10.00 mL, that is a tenfold
dilution. If 0.50 mL of that solution is then diluted to 5.00 mL, the
combined factor is 100—not 20 and not 15.

The full calculation should preserve units and actual volumes.
Spreadsheet formulas should be controlled, checked and protected from
accidental changes.

Percent,
milligrams per gram and parts per million

For a mass-by-mass result:

• 1% = 10 mg/g
• 0.1% = 1 mg/g
• 0.01% = 0.1 mg/g = 100 µg/g = 100 ppm
• 1 ppm = 1 µg/g for mass-by-mass reporting

These conversions do not resolve the reporting basis. A result may be
reported as received, on a dry-weight basis, per total alkaloids, per
serving, per capsule or per milliliter. The denominator must be
stated.

Dry-weight correction

Suppose an as-received result is 0.038% 7-OH and the sample is 5%
moisture. A simplified dry-weight conversion is:

0.038% ÷ (1 − 0.05) = 0.040% dry weight

That difference could matter near a legal or specification threshold.
The moisture method, sample relationship, significant figures and
measurement uncertainty also matter. The example is educational and does
not classify any product as legal.

Per-serving conversion

A concentration result does not automatically establish milligrams
per serving. The laboratory or reviewer needs the mass or volume of the
serving and, for liquids, sometimes density.

For example, 0.020% by weight equals 0.2 mg/g. If a serving weighs 3
g, the arithmetic result is 0.6 mg per serving. That conversion is valid
only if the percentage and serving weight use compatible bases and the
sample represents the product.

Near
a legal or internal limit: calibration deserves extra scrutiny

A result close to a cutoff should not be treated as mathematically
exact. Review should consider:

• whether the cutoff and result use the same denominator;
• sample representativeness;
• reporting basis;
• calibration range;
• proximity to the lower or upper quantitation limit;
• standard uncertainty and purity;
• method recovery and precision;
• measurement uncertainty;
• rounding rules; and
• the decision rule used to classify pass or fail.

Different laws use different 7-OH thresholds and denominators. A
percentage of dry product weight is not interchangeable with a
percentage of total alkaloids or milligrams per serving. The best
calibration system cannot rescue a comparison made on the wrong
basis.

Until the federal 7-OH proceeding is final, a proposed federal
threshold should not be labeled as current federal law. State and local
restrictions may apply independently and can be stricter. Kiody’s
nationwide botanical-leaf and 7-OH trackers should be consulted before
commerce decisions.

Five fictional calibration
reviews

These examples are fictional and illustrate document review, not
actual Kiody lots or legal conclusions.

Example 1: The impressive
r²

A leaf-powder COA states “calibration r² = 0.9998.” No
curve range, back-calculated results, control recoveries or method scope
are available.

Assessment: The number is encouraging but
insufficient. Ask whether the sample fell within the calibrated range,
whether low-level standards met criteria and whether independent
controls passed.

Example 2: The expired
certificate

The laboratory provides a mitragynine standard certificate, but the
lot expired six months before the run. The lab has no documented
requalification.

Assessment: The assigned value may no longer be
defensible for the use. Request the requalification record or a
corrected analysis using a current qualified standard.

Example 3: The
same stock made everything pass

Calibrators and QC samples were all prepared from one stock solution
by the same analyst. A later review discovers that the purity correction
was omitted.

Assessment: Agreement among results did not expose
the common preparation error. An independently prepared QC could have
helped.

Example 4:
Plain-leaf method used for syrup

A lab verified a method using plain powder but applies it to a
flavored liquid without matrix-recovery evidence. The syrup produces a
low internal-standard response.

Assessment: The result needs a matrix-effect
investigation. Instrument sensitivity alone does not demonstrate that
the method works in syrup.

Example 5:
Above-range extract reported directly

An extract response exceeds the highest calibrator, but software
extrapolates a number and the COA reports it to four significant
figures.

Assessment: Extrapolation outside the demonstrated
range is not equivalent to quantitation within it. The sample should
normally be diluted and reanalyzed under the method’s validated
rules.

A
12-step review for a kratom laboratory’s calibration evidence

Step 1: Define the exact
analytes

Confirm whether the method measures mitragynine, 7-OH, named minor
alkaloids or manufactured derivatives. Do not accept “full alkaloid
panel” without the list.

Step 2: Match the product
matrix

Confirm that the method scope covers the tested form: leaf powder,
capsules, extract, liquid, enhanced material or multi-ingredient
product.

Step 3: Review
reference-standard certificates

Check producer, catalog, lot, identity, assigned value, uncertainty
or purity basis, storage and validity dates.

Step 4: Trace stock
preparation

Verify actual weights, volumes, purity corrections, equipment IDs,
calculations, preparer and reviewer.

Step 5: Review
working-standard traceability

Follow each dilution from primary stock to calibrator. Confirm units
and significant figures.

Step 6: Examine the curve
design

Check range, levels, blanks, model, weighting, replicate rules and
criteria.

Step 7: Look beyond r²

Review back-calculated concentrations, residuals and low-end
performance where available.

Step 8: Confirm
independent quality controls

Determine whether controls can detect a common stock or preparation
error.

Step 9:
Check system suitability and drift controls

Confirm that the run met predefined performance criteria from
beginning through end.

Step 10: Evaluate
matrix effects and recovery

Look for fortified-recovery, internal-standard, matrix-matching or
other fit-for-purpose evidence.

Step 11: Recalculate
the reported result

Verify sample weight, extract volume, every dilution, moisture or
density correction, and final units.

Step 12: Reconcile
report, lot and legal basis

Confirm that the reviewed data belong to the COA, product lot and
jurisdictional threshold being evaluated.

Twenty calibration warning
signs

1. “Calibrated” appears without saying what was calibrated.
2. The reference-standard producer or lot cannot be identified.
3. The certificate is missing, expired or for a different chemical
   form.
4. Purity is entered as 100% without support.
5. Stock-solution preparation has no independent review.
6. Calibrators and controls all come from the same stock with no
   independent check.
7. The curve range is undisclosed.
8. The sample result lies outside the curve range.
9. The laboratory relies on r² as the only curve
   criterion.
10. Curve points are deleted without a documented technical reason.
11. The regression model changes after sample results are viewed.
12. No method blank or carryover check is used where needed.
13. A high-concentration sample immediately precedes a trace-level
    sample with no carryover assessment.
14. The internal-standard response is abnormal but ignored.
15. A plain-leaf validation is assumed to cover liquids, gummies or
    enhanced products.
16. Dilution factors cannot be reconstructed.
17. Percent, ppm, mg/g and mg/serving are used interchangeably.
18. Dry-weight and as-received results are compared without
    correction.
19. Failing controls disappear from the final record.
20. The COA reports more decimal places than the method can
    support.

One warning sign does not prove a result is false. It identifies the
next question to ask.

A practical
calibration-record template

For each quantitative analyte and run, a defensible record may
include:

Method and scope

• method title and identifier;
• current version and effective date;
• analyte list;
• accepted matrices;
• instrument platform;
• validated range;
• LOD, LOQ and reporting limit;
• reporting basis and units; and
• relevant specification or decision point.

Reference standard

• analyte name;
• chemical form and identifier;
• producer;
• catalog number;
• lot number;
• certificate number and version;
• assigned value or purity;
• correction basis;
• uncertainty, when supplied;
• receipt date;
• opened date;
• storage condition;
• expiration or requalification date; and
• qualification against a primary standard, when applicable.

Stock and working solutions

• solution ID;
• parent standard or solution ID;
• actual mass or volume;
• equipment IDs;
• solvent and lot;
• final volume or mass;
• full concentration calculation;
• preparer;
• verifier;
• preparation time;
• storage condition; and
• use-by time.

Curve and run

• run or sequence ID;
• calibration levels;
• blank types;
• model and weighting;
• acceptance criteria;
• back-calculated results;
• excluded points and reasons;
• system-suitability results;
• continuing checks;
• carryover checks;
• internal-standard response review; and
• instrument or software audit trail reference.

Quality control and samples

• QC identities and preparation source;
• target levels;
• observed results and recoveries;
• duplicate agreement;
• matrix-spike results;
• sample ID and lot;
• sample weight or volume;
• extraction volume;
• dilution steps;
• instrument result;
• final calculation;
• moisture, density or serving conversion;
• deviations and investigations; and
• analyst and reviewer approval.

This is a review framework, not a universal form or legal
requirement. The laboratory’s controlled procedure should determine
which fields apply.

Frequently asked questions

1.
Does a calibration curve prove a kratom result is accurate?

No. It supports the relationship between known standards and
response. Accuracy also depends on reference values, sample preparation,
matrix performance, calculations, controls and representative
sampling.

2. Is r² = 0.999 enough?

No. Review individual standard accuracy, residuals, range, controls
and predefined acceptance criteria. A high r² alone can
hide poor low-level performance.

3. What is a
mitragynine reference standard?

It is a characterized material used to establish or check
measurements of mitragynine. Its producer, lot, assigned value, chemical
form, storage and certificate should be documented.

4. Does NIST
certify every kratom alkaloid standard?

No. NIST produces many Standard Reference Materials, but a chemical
supplier’s standard should not be described as a NIST SRM unless it
actually is one. Laboratories may use other suitable qualified
materials.

5. What is a
stable-isotope internal standard?

It is a chemically similar compound labeled with stable isotopes so
the instrument can distinguish it from the analyte. It may help track
variation, but it does not replace analyte standards or validation.

6. Why use more than
one calibration level?

Multiple levels help establish how response changes across a range
and whether the selected model performs adequately where samples are
measured.

7. Can a
laboratory report above its highest calibrator?

It should follow its validated procedure. Commonly, an above-range
sample is diluted and reanalyzed rather than assigned a precise result
by unsupported extrapolation.

8. What happens
below the quantitation limit?

The method should define how results below its quantitative
capability are reported. A detected signal is not automatically a
reliable numerical concentration.

9. Are calibration
acceptance rules universal?

No. Criteria depend on method, analyte, matrix, intended use and
governing requirements. A criterion from one FDA drug or food method
should not be copied into kratom testing without scientific
justification.

10. Why does matrix matching
matter?

Plant material and other ingredients can change extraction or
detector response. Matrix-matched standards or other validated controls
can help assess or reduce that influence.

11. What is system
suitability?

It is a pre-defined check that the analytical system is performing
adequately for the run. It can evaluate response, repeatability,
separation, peak shape and other method-specific measures.

12. What is a
continuing calibration check?

It is a standard analyzed during or after a batch to evaluate whether
instrument response remains acceptable after the initial
calibration.

13.
Can one alkaloid standard quantify every kratom alkaloid?

Not automatically. Different compounds can produce different
responses. A method needs analyte-specific or scientifically justified
response assumptions within its validated scope.

14. Can the
same calibration cover leaf and extract?

Possibly, with suitable dilution and verified matrix performance, but
it cannot be assumed. Extracts may exceed the range or behave
differently during preparation and detection.

15. Why
are dry-weight and as-received results different?

Dry-weight reporting removes the measured moisture fraction from the
denominator. The difference becomes more important near a numerical
threshold.

16.
Does “ISO/IEC 17025 accredited” prove every reported analyte is in
scope?

No. Review the laboratory’s current accreditation scope, location,
method, matrix and analyte coverage. Accreditation is important
evidence, not blanket product approval.

17.
Does this calibration guidance prove kratom is FDA approved?

No. FDA’s laboratory principles are used here to explain measurement
quality. They do not change FDA’s legal position on kratom products.

18. What should a buyer
ask for first?

Ask for the lot-specific COA, method identifier, reporting basis,
laboratory accreditation scope and confirmation that reference
standards, calibration and independent controls were current and
acceptable for that run.

Current federal
note as of September 3, 2026

The legal categories must remain separate from the analytical
categories:

• The federal proceeding concerning 7-OH above a specified threshold
  remains pending. HHS extended comments through September 10,
  2026. A proposed threshold is not yet a final federal
  scheduling rule.
• DEA’s separate temporary order placed MGPI, MGM-15 and
  MGM-16 in Schedule I from August 26, 2026, through
  August 26, 2028, unless extended or made permanent.
• DOJ states that its action targets deliberately manufactured and
  concentrated products rather than traditional botanical kratom. DOJ also
  states that it will use enforcement discretion when only incidental
  trace MGPI is confirmed in a product otherwise consistent with botanical
  kratom. That policy is not a legal exemption, gives no
  numerical trace threshold and does not apply to MGM-15, MGM-16 or
  intentionally added, manufactured, concentrated or fortified MGPI.
• State and local rules can independently restrict botanical leaf,
  7-OH or related products. A technically sound result does not itself
  establish legality.

Kiody does not sell concentrated 7-OH, MGPI, MGM-15 or MGM-16. Any
legal-status claim should be checked against current official sources
and Kiody’s current nationwide trackers.

Key takeaways

• An instrument signal becomes a reported concentration only through a
  documented measurement chain.
• Reference-standard identity, assigned value, chemical form, storage
  and validity matter.
• A high r² does not by itself establish an accurate
  curve.
• Calibration range must match the sample after valid dilution.
• Independent controls can reveal mistakes shared by all curve
  standards.
• Botanical powder, capsules, liquids, extracts and enhanced products
  are different analytical matrices.
• Percent, ppm, dry weight, total-alkaloid fraction and milligrams per
  serving are different reporting bases.
• Calibration cannot correct poor sampling, wrong lot identity or
  incorrect legal interpretation.
• Ordinary botanical leaf should not be conflated with concentrated
  7-OH or federally controlled manufactured derivatives.

Sources

• 21
  CFR §111.320 — Laboratory methods for testing and examination
• FDA Guidelines
  for the Validation of Chemical Methods for the FVM Program, Third
  Edition
• FDA
  Questions and Answers on CGMP Laboratory Controls
• NIST Standard Reference Materials
  program
• NIST Policy
  on Metrological Traceability
• FDA Q2(R2)
  Validation of Analytical Procedures
• FDA’s
  current kratom page
• HHS
  7-OH threshold proceeding and September 10 comment deadline
• DEA
  temporary Schedule I order for MGPI, MGM-15 and MGM-16
• DOJ
  September 1, 2026 incidental-trace MGPI clarification