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The Omega Laboratories Hair Drug Screening Assay Phencyclidine is an in vitro diagnostic test that is intended to be used for the determination of the presence of PCP in human hair from the head and body. The Omega Laboratories Hair Drug Screening Assay utilizes an enzyme linked immunosorbent assay (ELISA) for PCP, for the qualitative detection of PCP at or above 300 pg/mg of hair for the purpose of identifying the use of PCP. To confirm a screen positive result, a more specific alternate chemical method, such as Gas Chromatography/Mass Spectrometry (GC/MS) operating in the selected ion monitoring (SIM) mode is the preferred method with deuterated internal standards. Professional judgment should be applied to any drug of abuse test result, particularly when presumptive positive results are obtained.

This test is intended exclusively for single laboratory use only and is not intended for sale to anyone.

The Assay is an enzyme immunoassay for the qualitative detection of phencyclidine in head and body hair (hair). Phencyclidine (PCP), the hallucinogen commonly referred to as Angel Dust, can be detected in hair.

The assay consists of two parts; a pre-analytical proprietary and patent pending hair treatment procedure (to remove PCP from the solid hair matrix to a measurable liquid matrix), and the screening assay. The screening assay is an Enzyme-Linked ImmunoSorbent Assay (ELISA).

After the extraction treatment, the test sample is added to a well of the coated micro strip plate and enzyme conjugate is added, followed by incubation. During this phase the enzyme-labeled drug conjugate competes with drug in the sample for a limited number of binding sites on the antibody-coated micro wells. The two bind in proportion to their concentrations. A wash solution is applied to remove any unbound materials. Enzyme substrate solution containing a chromagen is added. The reaction is stopped with an acid and the absorbance is read using a plate reader at 450 nm. A background reading is also taken at 630 nm. Color intensity is inversely proportional to the amount of drug present in the sample. For the screening of PCP in hair, an enzyme linked immunosorbent assay (ELISA) procedure has been established.

Acceptance Criteria and Device Performance for Omega Laboratories Hair Drug Screening Assay Phencyclidine (K131181)

The Omega Laboratories Hair Drug Screening Assay Phencyclidine (PCP) is an in vitro diagnostic test for the qualitative detection of PCP in human head and body hair at or above 300 pg/mg.

1. Table of Acceptance Criteria and Reported Device Performance

The provided document does not explicitly state pre-defined acceptance criteria (e.g., target true positive rate, true negative rate, or specific ranges for precision values) against which the study results are directly measured. However, the studies demonstrate the precision, agreement with a reference method, and robustness of the assay. The performance is reported in terms of observed precision and agreement rates.

2. Sample Sizes Used for the Test Set and Data Provenance

• Agreement Study (Primary Test Set): A total of 393 donor hair samples.

  • Data Provenance: The document does not explicitly state the country of origin.
  • Retrospective/Prospective: Not specified. The original study (K101059) included 352 samples, and a second study added 41 more, suggesting they were previously collected donor samples.

• Precision Studies:

  • Intra-assay (Individual): 5 hair specimens, each divided into 6 aliquots (3 aliquots analyzed), yielding a total of 15 test measurements.
  • Intra-assay (Spiked): 11 replicates for 8 concentrations, totaling 88 test measurements.
  • Inter-assay (Spiked): 11 replicates for 8 concentrations, analyzed over 20 non-consecutive days, totaling 220 test measurements for each concentration (1760 total measurements).

• Cosmetic Treatment Study:

  • Negative Samples: n=86 samples.
  • Positive Samples: n=89 samples.

• Cross-reactivity: Tested against 273 compounds (Phencyclidine, 4 structurally similar compounds, and 269 other compounds mentioned as "None of the other (270) compounds").

• Shipping Study: n=137 head hair samples (30 positive, 100 negative, 7 near cutoff).

• Stability Study (Long-term Storage): n=137 head hair samples.

3. Number of Experts and Qualifications for Ground Truth

The document does not explicitly state the number or qualifications of experts used to establish ground truth for the ELISA assay itself, as the gold standard for confirmation is typically a different analytical method.

For the Agreement Study, the ground truth was established by Gas Chromatography/Mass Spectrometry (GC/MS) operating in selected ion monitoring (SIM) mode with deuterated internal standards. This is an objective, analytical method, not typically relying on expert interpretation in the same way as, for example, medical imaging. Therefore, "experts" in the sense of trained clinicians making diagnoses are not applicable here. The GC/MS analysis itself requires trained laboratory personnel.

4. Adjudication Method for the Test Set

Not applicable in the traditional sense for this type of analytical device. The "ground truth" for the test set in the Agreement Study was determined by GC/MS results. The ELISA results were then compared directly against these quantitative GC/MS measurements. There was no human consensus or adjudication process described for reconciling discrepancies between the ELISA and GC/MS results; discrepancies were simply reported (Table 7).

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, an MRMC comparative effectiveness study was not performed. This type of study is typically used for diagnostic devices that involve human interpretation (e.g., radiological images) where the performance of human readers with and without AI assistance is compared. The Omega Laboratories Hair Drug Screening Assay Phencyclidine is an automated in vitro diagnostic assay, not one that involves human "readers" interpreting results in a subjective manner that would be assisted by AI.

6. Standalone Performance

Yes, a standalone performance study was performed (algorithm only without human-in-the-loop performance). The entire performance summary (sections 6.1 through 6.9) describes the analytical performance of the ELISA assay as a standalone system.

• Precision studies (Intra-assay and Inter-assay): Demonstrate the reproducibility of the device's output.
• Agreement Study: Compares the device's output directly against a gold standard analytical method (GC/MS) without human intervention in the device's determination.
• Cosmetic Treatment, Cross-reactivity, Shipping, and Stability Studies: Evaluate the robustness and analytical validity of the device's performance under various conditions.

7. Type of Ground Truth Used

The ground truth used for the primary performance assessment (Agreement Study) was quantitative Gas Chromatography/Mass Spectrometry (GC/MS) results with deuterated internal standards. This is an objective, analytical "confirmatory method" that scientifically determines the presence and concentration of PCP in the hair samples.

8. Sample Size for the Training Set

The document does not provide information on a specific training set size. As this is a 510(k) submission for an enzyme immunoassay, the development process typically involves assay optimization and validation. It's common for such devices not to have a distinct "training set" in the machine learning sense, but rather a development and optimization phase where parameters are set using various samples, followed by independent validation (the "test set" described in the performance summary).

9. How the Ground Truth for the Training Set Was Established

Since a distinct "training set" is not explicitly mentioned or characterized in terms of ground truth establishment, this information is not provided in the document. The overall assay development and optimization (which can be considered analogous to a training phase) would have relied on established analytical chemistry principles and potentially internal reference methods to ensure the assay's ability to detect PCP and quantify its presence relative to the cutoff.

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