Does a split specimen bottle for drug screening require validity testing?

From the Guidelines

No, a split specimen bottle for drug screening does not require validity testing. When a drug test is conducted using a split specimen collection method, the original sample is divided into two containers. Validity testing, which checks for sample adulteration, dilution, or substitution, is typically performed on the initial specimen during the screening process 1.

Key Points to Consider

• The purpose of a split specimen is to confirm the presence of specific substances detected in the initial screening, ensuring accuracy and providing individuals with an opportunity to challenge positive results.
• Validity testing has already been performed on the original specimen, making it unnecessary to repeat these tests on the split specimen.
• The approach of not requiring validity testing on the split specimen maintains testing integrity while avoiding unnecessary duplicate testing.
• According to the study on good laboratory practices for molecular genetic testing for heritable diseases and conditions, split specimens are used for testing by another method or in another laboratory, but this does not imply the need for validity testing on the split specimen itself 1.
• The focus is on confirming the specific substances found, rather than re-evaluating the specimen's validity.

From the Research

Specimen Validity Testing for Drug Screening

• The use of a split specimen bottle for drug screening requires validity testing to ensure the accuracy and reliability of the test results 2.
• Validity testing is an essential component of the drug testing process, as it helps to detect any potential interference or adulteration of the specimen 3, 4.
• The testing process involves several steps, including specimen collection, analysis, and confirmation, and each step must be carefully controlled to ensure the integrity of the specimen 2, 5.

Importance of Validity Testing

• Validity testing is crucial in preventing false positive or false negative results, which can have serious consequences for individuals undergoing drug testing 4.
• The use of synthetic urine products, which can yield negative drug screen results, highlights the need for effective validity testing methods 3.
• Advances in technology, such as liquid chromatography tandem mass spectrometry (LC-MS/MS) and high-resolution mass spectrometry, have improved the detection of non-physiologic specimens and enhanced the accuracy of drug testing results 3, 6.

Requirements for Specimen Validity Testing

• Specimen validity testing must be performed in accordance with established guidelines and regulations, including those related to chain of custody, quality control, and result interpretation 2, 4.
• The testing process must be conducted by qualified and experienced individuals using proper laboratory equipment and techniques 4.
• The use of multiple validity markers, such as caffeine, cotinine, and urobilin, can help to detect non-physiologic specimens and ensure the accuracy of drug testing results 3.