How should the results of the Cannabis Typification or 4-AP field test be interpreted?

The results from the Cannabis Typification or 4-AP field test can be interpreted in one of four ways:

  • Blue color formation: Indicative of Marijuana (delta-9-THC concentration is greater than that of Cannabidiol).  The sample should be submitted to DFS for further analysis if criminal charges are to be pursued (excluding simple possession of marijuana cases that may only be submitted with a court order).
  • Pink color formation: Indicative of Hemp (Cannabidiol concentration is greater than that of delta-9-THC).  This sample should not be submitted to the lab for further testing unless the adjudication of the case hinges upon THC concentration determination down to 0.3% as defined in the Code of Virginia.  This method is currently being developed and validated by the Department.
  • Purple or dark blue color formation: Inconclusive result.  The test was likely conducted using too much plant material, and should be performed again using a fresh test kit and an appropriate amount of sample.  The appropriate amount of sample should be about the size of a grain of rice.
  • No color change: Inconclusive result.  Repeat the test again using a fresh test kit with an appropriate amount of sample.  The appropriate amount of sample should be about the size of a grain of rice.

For more information, please see the 4-AP informational page: https://www.dfs.virginia.gov/field-test-kits/4-ap-cannabis-typification-field-tests/

Can you walk me through how and when to use the Cannabis Typification or 4-AP field test?

Please see the Department’s website for both written instructions and an instructional video on how to use this test kit.  The direct link for this information can be found at: https://www.dfs.virginia.gov/field-test-kits/4-ap-cannabis-typification-field-tests/

These tests should be used on plant material that has tested positive for Cannabis using the Duquenois-Levine test kit, and further information is needed as to whether it is more likely to be marijuana or industrial hemp.

What if the results of the marijuana field test kit are inconclusive?

If the Duquenois-Levine test is positive and the results of the Cannabis Typification or 4-AP field test are inconclusive, meaning there is no color change or it turned purple, repeat with another test kit on a separate sample.  A color change to purple may indicate the sample size is too large. Consider submitting evidence when results remain inconclusive (excluding simple possession of marijuana cases that may only be submitted with a court order). For § 18.2-250.1 offenses on or after July 1, 2020, the evidence will need to be accompanied with a court order at the time of submission.  Note on the Request for Laboratory Examination (RFLE) that the field test results were inconclusive.