D.C. Mun. Regs. tit. 22-C, § 6502
6502.1 Each testing laboratory shall:
6502.2 A testing laboratory shall use, when available, testing methods that have undergone validation by the “Official Methods of Analysis of AOAC International,” the Performance Tested Methods Program of the Research Institute of AOAC International, the “Bacteriological Analytical Manual” of the Food and Drug Administration, the International Organization for Standardization, the United States Pharmacopeia, the “Microbiology Laboratory Guidebook” of the Food Safety and Inspection Service of the United States Department of Agriculture or an equivalent third-party validation study approved by the Board.
6502.3 A testing laboratory shall test and analyze a statistically representative sample from each batch of medical cannabis or medical cannabis products for, at minimum:
(c) Cannabinoid potency, including, at minimum, the levels of the following:
(1) Delta-9-tetrahydrocannabinolic acid (THCA);
(2) Delta-9-tetrahydrocannabinol (THC);
(3) Cannabidiolic acid (CBDA);
(4) Cannabidiol (CBD); and
(5) Cannabinol (CBN);
(d) Foreign matter contamination;
(e) Microbial contamination;
(f) Mycotoxin contamination;
(g) Heavy metal contamination, including, at minimum, arsenic, cadmium, lead, and mercury;
(h) Pesticide and fertilizer residue,
(i) Residual solvents;
(j) Cannabinoid and Terpene Profile;
(k) Product Assessment (for edible products);
(l) Homogeneity (for edible products); and
(m) Any other items requested by or approved by the Board.
6502.4 All samples shall be personally selected and collected by the testing laboratory personnel on site at the cultivation center.
6502.5 The samples personally selected and collected by the testing laboratory shall include, at a minimum:
(a) One (1) testable sample of the final product of flower, from each harvest for every strain of medical cannabis grown by the cultivation center;
(b) One (1) testable sample of the final product of flower stored and packaged at the internet retailer or retailer; and
(c) One (1) testable sample of each type of product produced from each batch of medical cannabis, such as but not limited to, the following:
(1) Tincture;
(2) Topical;
(3) Shatter;
(4) Oils;
(5) Edibles;
(6) Wax;
(7) Kief; and
(8) Hash.
6502.6 A testing laboratory shall timely upload into the tracking system the test results for each batch of medical cannabis or medical cannabis product tested.
6502.7 The testing laboratory may retest or reanalyze the sample or a different sample from the same batch by following its standard operating procedures to confirm or refute the original result, upon request by the cultivation center or upon request by the Board at the cultivation center's expense.
6502.8 A testing laboratory shall implement an acceptable method of testing, such as, but not limited to:
(a) Gas Chromatography;
(b) Gas Chromatography Mass Spectrometry;
(c) Immunoassays;
(d) Thin Layer Chromatography;
(e) High Performance Liquid Chromatography; and
(f) Liquid Chromatography Mass Spectroscopy.
6502.9 A testing laboratory using Gas Chromatography shall perform and maintain records of the following, which shall be readily available to the staff operating the equipment:
(a) Document the conditions of the gas chromatograph, including the detector
response;
(b) Perform and document preventive maintenance as required by the manufacturer;
(c) Document the performance of new columns before use;
(d) Use an internal standard for each qualitative and quantitative analysis that has similar chemical and physical properties to that of the compound identified;
(e) Establish criteria of acceptability for variances between different aliquots and different columns; and
(f) Document the monitoring of the response (area or peak height) of the internal standard to ensure consistency overtime of the analytical system.
6502.10 A testing laboratory using Gas Chromatography Mass Spectrometry shall perform and maintain records of the following, which shall be readily available to the staff operating the equipment:
(a) Perform and document preventive maintenance as required by the manufacturer;
(b) Document the changes of septa as specified in the standard operating procedure;
(c) Document liners being cleaned or replaced as specified in the standard operating procedure;
(d) Maintain records of mass spectrometer tuning;
(e) Establish written criteria for an acceptable mass spectrometer tune;
(f) Document corrective actions if a mass spectrometer tune is unacceptable;
(g) Monitor analytic analyses to check for contamination and carry-over;
(h) Use selected ion monitoring within each run to assure that the laboratory compares ion ratios and retention times between calibrators, controls and samples for identification of an analyte;
(i) Use an internal standard for qualitative and quantitative analysis that has similar chemical and physical properties to that of the compound
identified and is isotopically labeled when available or appropriate for the assay;
(j) Document the monitoring of the response (area or peak height) for the internal standard to ensure consistency overtime of the analytical system;
(k) Define the criteria for designating qualitative results as positive;
(l) Ensure that when a library is used to qualitatively match an analyte, the relative retention time and mass spectra from a known standard or control shall be run on the same system before reporting the results; and
(m) Evaluate the performance of the instrument after routine and preventive maintenance (such as clipping or replacing the column or cleaning the source) prior to analyzing subject samples.
6502.11 A testing laboratory using Immunoassays shall perform and maintain records of the following, which shall be readily available to the staff operating the equipment:
(a) Perform and document preventive maintenance as required by the manufacturer;
(b) Validate any changes or modifications to a manufacturer's approved assays or testing methods when the sample being tested is not included in the list of samples approved for assaying or testing by the manufacturer; and
(c) Define acceptable separation or measurement units (absorbance intensity or counts per minute) for each assay, which shall be consistent with the manufacturer's instructions.
6502.12 A testing laboratory using Thin Layer Chromatography shall perform and maintain records of the following, which shall be readily available to the staff operating the equipment:
(a) Apply unextracted standards to each thin layer chromatographic plate;
(b) Include in its standard operating procedures the preparation of mixed solvent systems, spray reagents and designation of their lifetimes;
(c) Include in its standard operating procedures the storage of unused thin layer chromatographic plates;
(d) Evaluate, establish, and document acceptable performance for new thin
layer chromatographic plates before placing them into service;
(e) Verify that the spotting technique used precludes the possibility of contamination and carry-over;
(f) Measure all appropriate Rf values for qualitative identification purposes;
(g) Use and record sequential color reactions, when applicable;
(h) Maintain a copy of the developer TLC plates for each bath of samples analyzed; and
(i) Analyze an appropriate matrix blank with each batch of samples analyzed.
6502.13 A testing laboratory using High Performance Liquid Chromatography shall perform and maintain records of the following, which shall be readily available to the staff operating the equipment:
(a) Perform and document preventive maintenance as required by the manufacturer;
(b) Monitor and document the performance of the HPLC instrument each day of testing;
(c) Document the performance of new columns before use;
(d) Create standard operating procedures for acceptability when eluting solvents are recycled;
(e) Use an internal standard for each qualitative and quantitative analysis that has similar chemical and physical properties to that of the compound identified when available or appropriate for the assay; and
(f) Document the monitoring of the response (area or peak height) of the internal standard to ensure consistency overtime of the analytical system.
6502.14 A testing laboratory using Liquid Chromatography Mass Spectroscopy shall perform and maintain records of the following, which shall be readily available to the staff operating the equipment:
(a) Perform and document preventive maintenance as required by the manufacturer;
(b) Maintain records of mass spectrometer tuning;
(c) Document corrective actions if a mass spectrometer tune is unacceptable;
(d) Use an internal standard with each qualitative and quantitative analysis that has similar chemical and physical properties to that of the compound identified and is isotopically labeled when available or appropriate for the assay;
(e) Document the monitoring of the response (area or peak height) of the internal standard to ensure consistency overtime of the analytical system;
(f) Compare two transitions and retention times between calibrators, controls and samples within each run;
(g) Document and maintain records when changes in source, source conditions, eluent, or column are made to the instrument; and
(h) Evaluate the performance of the instrument when changes in source, source conditions, eluent, or to a column are made prior to reporting test results.
6502.15 A testing laboratory shall determine if the following pesticides are within the acceptable limit using the following chart:
| Insecticide | Critical Limit |
|---|---|
| Acetamiprid | 0.2 |
| Abamectin | 0.5 |
| Aldicarb | 0.4 |
| Bifenazate | 0.2 |
| Carbofuran | 0.2 |
| Chlorantraniliprole | 0.2 |
| Chlorpyrifos | 0.2 |
| Cyfluthrin | 1.0 |
| DDVP (Dichlorvos) | 0.1 |
| Diazinon | 0.2 |
| Dimethoate | 0.2 |
| Fenpyroximate | 0.5 |
| Fipronil | 0.4 |
|---|---|
| Flonicamid | 1.0 |
| Imidacloprid | 0.4 |
| Malathion | 0.2 |
| Methiocarb | 0.2 |
| Methomyl | 0.4 |
| Naled | 0.5 |
| Oxamyl | 1.0 |
| Permethrin | 0.5 |
| Phosmet | 0.2 |
| Piperonyl butoxide | 1.0 |
| Pyrethrins | 1.0 |
| Spinosad | 0.2 |
| Spiromesifen | 0.2 |
| Spirotetramat | 0.2 |
| Thiacloprid | 0.2 |
| Thiamethoxam | 0.2 |
6502.16 A testing laboratory shall determine if the following plant growth regulators are within the acceptable limit using the following chart:
| Table B. Plant Growth Regulator Critical Limits in Parts Per Million (PPM) | |
|---|---|
| Plant Growth Regulator | Critical Limit |
| Ancymidol | 0.2 |
| Carbaryl | 0.2 |
| Daminozide (Alar) | 0.1 |
| Ethephon | 1.0 |
| Flurprimidol | 0.2 |
| Paclobutrazol | 0.4 |
6502.17 A testing laboratory shall determine if the following fungicides are within the acceptable limit using the following chart:
| Table C. Fungicide Critical Limits in Parts Per Million (PPM) | |
|---|---|
| Fungicide | Critical |
| Limit | |
|---|---|
| Azoxystrobin | 0.2 |
| Bifenthrin | 0.2 |
| Boscalid | 0.4 |
| Fludioxonil | 0.4 |
| Imazalil | 0.2 |
| Kresoxim-methyl | 0.4 |
| Metalaxyl | 0.2 |
| Myclobutanil | 0.2 |
| Propiconazole | 0.4 |
| Trifloxystrobin | 0.2 |
6502.18 A testing laboratory shall determine if the following acaricides are within the acceptable limit using the following chart:
| Table D. Acaricide Critical Limits in Parts Per Million (PPM) | |
|---|---|
| Acaricide | Critical Limit |
| Clofentezine | 0.2 |
| Etoxazole | 0.2 |
6502.19 A testing laboratory shall determine if the following ovicide is within the acceptable limit using the following chart:
| Table E. Ovicide Critical Limits in Parts Per Million (PPM) | |
|---|---|
| Ovicide | Critical Limit |
| Hexythiazox | 1.0 |
6502.20 [REPEALED].
6502.21 A testing laboratory shall determine if the following microbial impurities are within the acceptable limit using the following chart:
| Table G. Microbiological Impurity Critical Limits in Colony Forming Units (CFU/g) | |
|---|---|
| Microbiological | Critical |
| Impurity | Limit |
|---|---|
| E. coli | < 100 |
| Salmonella spp. | 0 |
| Total Aerobic Microbial Count | 100,000 |
| Total Yeast and Mold Count | 100,000 |
6502.22 A testing laboratory shall determine if the following heavy metals are within the acceptable limit using the following chart:
| Table H. Heavy Metal Critical Limits in Parts Per Million (PPM) | |
|---|---|
| Heavy Metal | Critical Limit |
| Arsenic | 0.4 |
| Barium | 60.0 |
| Cadmium | 0.4 |
| Chromium | 0.6 |
| Lead | < 1.0 |
| Mercury | 0.2 |
| Selenium | 26.0 |
| Silver | 1.4 |
6502.23 A testing laboratory shall determine if the Water Activity ($A_w$) of a sample is within an acceptable limit. For purposes of this section, the $A_w$ of a sample shall be acceptable if it is below $0.65A_w$.
6502.24 A testing laboratory shall determine if an edible is a potentially hazardous food by using the following charts:
| Table I. Interaction of pH and $A_w$ for control of spores in food heat-treated to destroy Vegetative cells and subsequently packaged | |||
|---|---|---|---|
| $A_w$ values | pH values | ||
| 4.6 or less | > 4.6 – 5.6 | > 5.6 | |
| ≤0.92 | Non-PHF*/non-TCS food | Non-PHF/non-TCS food | Non-PHF/non-TCS food |
| > 0.92 - .95 | Non-PHF/non-TCS food | Non-PHF/non-TCS food | PA* |
| > 0.95 | Non-PHF/non-TCS food | PA | PA |
| * PHF means Potentially Hazardous Food TCS Food means Time/Temperature Control for Safety Food * PA means Product Assessment required |
Table J. Interaction of pH and $A_w$ for control of vegetative cells and spores in food not heat-treated but not packaged
| $A_w$ values | pH values | |||
|---|---|---|---|---|
| < 4.2 | 4.2 – 4.6 | > 4.6 – 5.0 | > 5.0 | |
| < 0.88 | non-PHF/non-TCS food* | non-PHF/non-TCS food | non-PHF/non-TCS food | non-PHF/non-TCS food |
| 0.88 – 0.90 | non-PHF/non-TCS food | non-PHF/non-TCS food | non-PHF/non-TCS food | PA*** |
| > 0.90 – 0.92 | non-PHF/non-TCS food | non-PHF/non-TCS food | PA | PA |
| > 0.92 | non-PHF/non-TCS food | PA | PA | PA |
| * PHF means Potentially Hazardous Food ** TCS Food means Time/Temperature Control for Safety Food *** PA means Product Assessment required |
SOURCE: Final Rulemaking published at 73 DCR 002136 (February 20, 2026).