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510(k) Data Aggregation
(300 days)
The Psychemedics Microplate EIA for Cannabinoids in Hair is an enzyme immunoassay (EIA) for the preliminary qualitative detection of cannabinoids in human head and body hair samples using a 11-nor-9-Carboxy- Δ'-THC calibrator at 10 pg/10 mg hair cutoff for the purpose of identifying marijuana use. This is an in vitro diagnostic device intended exclusively for Psychemedics use only and is not intended for sale to anyone.
The Psychemedics Chemiluminscent Microplate EIA for Cannabinoids assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used in order to obtain a confirmed analytical result. Gas Chromatography/Mass Spectrometry/Mass Spectrometry (GC/MS/MS) is the preferred confirmatory method. Clinical consideration and professional judgment should be exercised with any drug of abuse test result, particularly when the preliminary result is positive.
The EIA screening test consists of two parts; a pre-analytical hair treatment procedure to recover the cannabinoids from the hair and the screening assay, the Psychemedics Chemiluminescent EIA for Cannabinoids in Hair. The device comprises a white microplate coated with the antigen (11-nor-9-carboxy-delta-8-tetrahydrocannabinol) conjugated to BSA, polyclonal rabbit anticannabinoid antibody, goat anti-rabbit secondary antibody conjugated to HRP (horseradish peroxidase), a chemiluminescent substrate, and platewashing buffer.
Here's a breakdown of the acceptance criteria and the study details for the Psychemedics Chemiluminescent Microplate EIA for Cannabinoids in Hair, based on the provided 510(k) summary:
Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly defined by demonstrating substantial equivalence to the predicate device and showing agreement with the confirmatory method (GC/MS/MS). While explicit percentage targets for sensitivity and specificity are not directly stated as "acceptance criteria," the performance in the agreement testing (both with the predicate and GC/MS/MS) is presented to show the device meets the regulatory requirements for substantial equivalence.
| Acceptance Criteria Category | Description | Reported Device Performance |
|---|---|---|
| Agreement with Predicate Device (EIA vs RIA) | Low discordance with the predicate device (Psychemedics Marijuana Screening and Confirmatory Test System, K011426) for preliminary qualitative detection of cannabinoids in hair. | Out of 610 hair samples: - EIA Positive, Predicate Negative: 4 - EIA Negative, Predicate Positive: 2 - EIA Positive, Predicate Positive: 189 - EIA Negative, Predicate Negative: 415 Discordance < 1% |
| Agreement with Confirmatory Method (EIA vs GC/MS/MS) | High agreement with Gas Chromatography/Mass Spectrometry/Mass Spectrometry (GC/MS/MS) for samples around and above the cutoff. The EIA should accurately identify negative and positive samples, especially those confirmed as positive by GC/MS/MS. A small number of false positives or false negatives by EIA near the cutoff is expected to be further addressed by confirmation. | Out of 318 samples confirmed by LC/MS/MS: - EIA Positive, GC/MS/MS Negative: 0 - EIA Positive, GC/MS/MS ≥ -50% Cutoff and < Cutoff: 5 - EIA Positive, GC/MS/MS ≥ Cutoff and < +50% Cutoff: 1 - EIA Positive, GC/MS/MS ≥ +50% Cutoff and < 100% Cutoff: 7 - EIA Positive, GC/MS/MS ≥ +100% Cutoff: 176 - EIA Negative, GC/MS/MS Negative: 127 - EIA Negative, GC/MS/MS ≥ -50% Cutoff and < Cutoff: 0 - EIA Negative, GC/MS/MS ≥ Cutoff and < +50% Cutoff: 1 - EIA Negative, GC/MS/MS ≥ +50% Cutoff and < 100% Cutoff: 0 - EIA Negative, GC/MS/MS ≥ +100% Cutoff: 1 |
| Precision (Intra-Assay & Inter-Assay) | Consistent and reproducible results across different levels (negative, positive, and various percentages around the cutoff) within a single assay run (intra-assay) and between different assay runs (inter-assay). | Intra-Assay (15 replicates per level): - Negative levels (-100% to -25%) all showed 15 negative results, 0 positive results. - Positive levels (+25% to +100%) all showed 0 negative results, 15 positive results. Inter-Assay (75 replicates per level): - Negative levels (-100% to -25%) all showed 75 negative results, 0 positive results. - Positive levels (+25% to +100%) all showed 0 negative results, 75 positive results. |
| Impact of Cosmetic Treatments | Cosmetic treatments (bleach, permanent wave, dye, relaxer, shampoo) should not cause false negative results in cannabinoid-positive hair samples and should not cause false positive results in cannabinoid-negative hair samples. | - Negative Samples (20 per treatment type): All remained negative after treatment. - Positive Samples (12 per treatment type): No positive samples became negative in the EIA after cosmetic treatments. Mean (Range) B/B0 x 100 values before and after treatment showed no significant trend towards false negatives. |
| Environmental Contamination | The device and subsequent confirmation method should be able to differentiate between environmental contamination (e.g., marijuana smoke) and actual drug use (presence of Carboxy-THC metabolite). Environmental contamination should not lead to false positives for Carboxy-THC after the wash procedure and GC/MS/MS confirmation. | - Smoke-contaminated samples (12): All were positive by EIA. GC/MS/MS showed no Carboxy-THC, but high THC (189-788 ng/10 mg hair). This demonstrates the EIA's sensitivity to environmental THC, but the crucial point is the absence of Carboxy-THC after the wash and GC/MS/MS. - Washed smoke-contaminated samples: No Carboxy-THC detected after standard wash procedure. - Water/saline soaked smoke-contaminated samples: Positive in EIA, but no Carboxy-THC detected by GC/MS/MS. |
| Cross-reactivity and Interference | The device should not cross-react with common interfering substances or show interference from other compounds that could lead to false positives or negatives. | - Cross-reactivity: Investigated for sixty-seven compounds. (Specific results not detailed, but the conclusion states "demonstrated the Cannabinoid EIA to be substantially equivalent with the predicate.") - Interference: Seventy-five compounds tested at +/- 50% of the cutoff showed no interference. |
| Stability of Calibrator and Control Solutions | Calibrator and control solutions should maintain stability for a specified period. | Stability in methanol was shown for 1 year for the carboxy-THC calibrator and control solutions. |
| Recovery Study | The recovery of cannabinoids from hair samples of marijuana users should be comparable to that of the predicate device. | Recovery of cannabinoids from hair of marijuana users was shown to be substantially equivalent to that of the predicate device. |
Study Details
2. Sample Size Used for the Test Set and Data Provenance
- Agreement Testing with Predicate Device:
- Sample Size: 610 hair samples (18.9% body hair, remainder head hair).
- Data Provenance: Not explicitly stated, but given it's Psychemedics' own product and existing predicate, it's likely internal laboratory data, possibly collected retrospectively from their testing services. No country of origin is specified.
- Agreement Testing with GC/MS/MS:
- Sample Size: 318 of the 610 samples after preliminary testing were further confirmed by LC/MS/MS.
- Data Provenance: Not explicitly stated.
- Cosmetic Treatment Studies:
- Negative Samples: 20 cannabinoid-negative hair samples (10 per brand for each cosmetic type).
- Positive Samples: 12 cannabinoid-positive hair samples (6 per brand for each cosmetic type).
- Data Provenance: Not explicitly stated.
- Contamination Study:
- Sample Size: 12 hair samples (various colors, including red).
- Data Provenance: Lab-generated (experimentally contaminated with marijuana smoke).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
- Agreement with Predicate Device: The "ground truth" for this comparison was the result from the predicate device (Psychemedics Marijuana Screening and Confirmatory Test System, using RIA and GC/MS/MS). This implies the ground truth was established by the predicate device's methodology, which includes laboratory analysis. No individual human experts are described as establishing this particular ground truth, but rather the established method.
- Agreement with Confirmatory Method (GC/MS/MS): The ground truth for this segment of the study was established by LC/MS/MS (Liquid Chromatography/Mass Spectrometry/Mass Spectrometry) which is stated elsewhere to be GC/MS/MS (Gas Chromatography/Mass Spectrometry/Mass Spectrometry), the "preferred confirmatory method" for drugs of abuse testing. This is a highly accurate analytical chemical method. No human experts are described as manually interpreting or establishing this ground truth, as it's an objective chemical measurement.
- Cosmetic Treatment and Contamination Studies: The ground truth for these was either inferred from known negative/positive status of samples (for cosmetic treatments) or the known contamination event and the subsequent GC/MS/MS analysis (for the contamination study). Again, no specific human experts are detailed for establishing this ground truth, it's based on analytical results.
4. Adjudication Method for the Test Set
The document does not describe an adjudication method involving human experts for resolving disagreements. The comparisons rely on:
- Direct comparison of the investigational device's EIA results against the predicate device's RIA results for agreement.
- Direct comparison of the investigational device's EIA results against the objective chemical analysis results from LC/MS/MS (or GC/MS/MS) as the definitive ground truth for drug presence.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No. This is an in vitro diagnostic device (EIA assay) for preliminary qualitative detection, not an imaging device or one that relies on human interpretation for its primary output. Therefore, an MRMC study is not applicable or described.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, the performance data presented (precision, agreement with predicate, agreement with GC/MS/MS, cosmetic treatment, contamination, cross-reactivity, interference, stability, recovery) are all reflective of the standalone performance of the Psychemedics Chemiluminescent Microplate EIA for Cannabinoids in Hair. The device itself performs the assay, and the results are read by a microplate reader. While a human initiates the test and interprets the final result in the context of a cutoff, the performance metrics reported are for the assay system's analytical capabilities without human interpretative intervention in the measurement itself. The device provides "only a preliminary analytical test result," emphasizing its standalone nature as a screening tool.
7. The Type of Ground Truth Used
The primary ground truth used is objective chemical analysis:
- For agreement studies, GC/MS/MS (Gas Chromatography/Mass Spectrometry/Mass Spectrometry) or LC/MS/MS (Liquid Chromatography/Mass Spectrometry/Mass Spectrometry) is explicitly stated as the preferred confirmatory method and was used to confirm 318 samples.
- The predicate device itself also uses mass spectrometry for confirmation as part of its "bipartite device." This implies an analytical, rather than expert consensus or pathology-based, ground truth.
8. The Sample Size for the Training Set
The document does not provide information about a "training set" for the device. As an immunoassay (EIA), this device likely uses a predetermined set of reagents and a fixed protocol, rather than a machine learning algorithm that requires a traditional training set. The development of the assay itself would have involved extensive R&D, but the data presented here are for validation and performance testing of the finalized assay.
9. How the Ground Truth for the Training Set Was Established
Since no explicit training set for an algorithm is mentioned, this question is not directly applicable. The assay's development and optimization would have relied on known positive and negative samples, with their true status confirmed by robust analytical methods like GC/MS/MS.
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