(50 days)
The LZI Hydrocodone Enzyme Immunoassay is intended for the qualitative and semi-quantitative determination of hydrocodone in human urine at the cutoff values of 100 and 300 ng/mL when calibrated against hydrocodone. The assay is designed for prescription use with a number of automated clinical chemistry analyzers.
The semi-quantitative mode is for purposes of (1) enabling laboratories to determine an appropriate dilution of the specimen for confirmation by a confirmatory method such as GCMS and LCMS or (2) permitting laboratories to establish quality control procedures.
The LZI Hydrocodone Drugs of Abuse (DAU) Calibrators are for use as calibrators in the qualitative and semi-quantitative calibration of the LZI Hydrocodone Enzyme Immunoassay at the cutoff values of 100 and 300 ng/mL.
The LZI Hydrocodone Drugs of Abuse (DAU) Controls are for use as assayed quality control materials to monitor the precision of the LZI Hydrocodone Enzyme Immunoassay at the cutoff values of 100 and 300 ng/mL.
The assay provides only a preliminary analytical result. A more specific alternative chemical method must be used in order to obtain a confirmed analytical result. Gas or liquid chromatography/mass spectrometry (GC/MS or LC/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 test result is positive.
The LZI Hydrocodone assay is a homogeneous enzyme immunoassay with ready-to-use liquid reagents. The assay is based on competition between drug in the sample and drug labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for a fixed amount of antibody in the reagent. Enzyme activity decreases upon binding to the antibody, and the drug concentration in the sample is measured in terms of enzyme activity. In the absence of drug in the sample, hydrocodone-labeled G6PDH conjugate is bound to antibody, and the enzyme activity is inhibited. On the other hand, when free drug is present in the sample, antibody would bind to free drug; the unbound hydrocodone-labeled G6PDH then exhibits its maximal enzyme activity. Active enzyme converts nicotinamide adenine dinucleotide (NAD) to NADH, resulting in an absorbance change that can be measured spectrophotometrically at 340 nm.
The LZI Hydrocodone Enzyme Immunoassay is a kit comprised of two reagents, an R1 and R2 which are bottled separately but sold together within the kit.
The Ri solution contains mouse monoclonal anti-hydrocodone antibody, glucose-6-phosphate (G6P) nicotinamide adenine dinucleotide (NAD), stabilizers, and sodium azide (0.09%) as a preservative. The R2 solution contains glucose-6-phosphate dehydrogenase (G6PDH) labeled with hydrocodone in buffer with sodium azide (0.09%) as preservative.
The LZI Hydrocodone Enzyme Immunoassay calibrators and controls designated for use at the 100 ng/mL cutoff contain 0, 50, 75, 100, 125, 150, and 300 ng/mL of hydrocodone in human urine with sodium azide (0.09%) as preservative. These five calibrators and two controls are sold as individual bottles.
The LZI Hydrocodone Enzyme Immunoassay calibrators and controls designated for use at the 300 ng/mL cutoff contain 0. 150. 225. 300. 375. 500. and 800 ng/mL of hydrocodone in human urine with sodium azide (0.09%) as preservative. These five calibrators and two controls are sold as individual bottles.
"The LZI Hydrocodone Enzyme Immunoassay is an in-vitro diagnostic device intended for the qualitative and semi-quantitative detection of hydrocodone in human urine. The device offers two cutoff values: 100 ng/mL and 300 ng/mL. The performance studies evaluate the device's precision, linearity, cross-reactivity, and interference with clinical samples for both cutoff values.
1. A table of acceptance criteria and the reported device performance:
The document primarily presents performance data rather than explicit acceptance criteria. However, for a device of this type, the expectation is high agreement with a gold standard (GC/MS or LC/MS) and consistent performance across various conditions. Based on the provided performance summaries, the implied acceptance criteria would relate to the percentage of agreement with the confirmatory method for clinical samples, and consistent performance for precision, linearity, and minimal interference.
Implied Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance (100 ng/mL Cutoff) | Reported Device Performance (300 ng/mL Cutoff) |
|---|---|---|---|
| Method Comparison (Clinical Samples) | High percentage agreement with GC/MS or LC/MS. | ||
| Near cutoff samples should exhibit predictable behavior (some disagreement expected at the exact cutoff, but generally high accuracy above and below). | Total Agreement: 92.5% | ||
| Discrepant Samples: |
- 3 GC/MS/LC/MS Negative samples were LZI EIA Positive (all near cutoff, e.g., 85.1 ng/mL, 97.0 ng/mL).
- 3 GC/MS/LC/MS Positive samples were LZI EIA Negative (all near cutoff, e.g., 128.8 ng/mL, 138.5 ng/mL, 146.5 ng/mL). | Total Agreement: 95.0%
Discrepant Samples: - 2 GC/MS/LC/MS Negative samples were LZI EIA Positive (both near cutoff, e.g., 206.9 ng/mL, 246.0 ng/mL).
- 2 GC/MS/LC/MS Positive samples were LZI EIA Negative (both near cutoff, e.g., 301.0 ng/mL, 306.2 ng/mL). |
| Precision | Consistent classification (positive/negative) for samples clearly above/below cutoff. Some variability allowed at cutoff. | Semi-Quantitative and Qualitative: Consistency for samples at -100.0% to -25.0% of cutoff (all negative) and +25.0% to +100.0% of cutoff (all positive).
At 100 ng/mL cutoff: - Semi-Quant: 43 Pos/45 Neg (Total 88)
- Qual: 28 Pos/60 Neg (Total 88) | Semi-Quantitative and Qualitative: Consistency for samples at -100.0% to -25.0% of cutoff (all negative) and +25.0% to +100.0% of cutoff (all positive).
At 300 ng/mL cutoff: - Semi-Quant: 47 Pos/41 Neg (Total 88)
- Qual: 51 Pos/37 Neg (Total 88) |
| Linearity (Recovery) | Percent recovery close to 100% for serially diluted samples over the assay range. | For samples from 25 ng/mL to 300 ng/mL, % Recovery ranged from 96.1% to 102.8%.
(5 ng/mL sample showed 73.6% recovery, 0 ng/mL showed N/A, 0.4 ng/mL determined).
Regression: y = 1.0139x - 1.174, r2 = 0.9995 | For samples from 100 ng/mL to 800 ng/mL, % Recovery ranged from 100.8% to 105.3%.
(10 ng/mL sample showed 124.6% recovery, 0 ng/mL showed N/A, 0.5 ng/mL determined).
Regression: y = 1.0316x + 1.1461, r2 = 0.9988 |
| Cross-reactivity | Minimal or no cross-reactivity with structurally unrelated compounds; quantified cross-reactivity for related compounds. | Quantified cross-reactivity for hydrocodone and metabolites (e.g., Hydromorphone 85.08%).
Structurally related compounds showed low % cross-reactivity (e.g., Oxycodone 2.1%).
No significant cross-reactivity with structurally unrelated compounds. | Quantified cross-reactivity for hydrocodone and metabolites (e.g., Hydromorphone 78.13%).
Structurally related compounds showed low % cross-reactivity (e.g., Oxycodone 0.08%).
No significant cross-reactivity with structurally unrelated compounds. |
| Interference (Endogenous, pH, Specific Gravity) | No significant interference observed, leading to correct classification (Neg/Pos) for control concentrations. | No significant undesired interference observed with tested endogenous substances, pH values (3-11), or specific gravity levels (1.000-1.030) for both negative (75 ng/mL) and positive (125 ng/mL) controls. | No significant undesired interference observed with tested endogenous substances, pH values (3-11), or specific gravity levels (1.000-1.030) for both negative (225 ng/mL) and positive (375 ng/mL) controls. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
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Sample Size for Test Set:
- Precision Studies: For the precision studies (both semi-quantitative and qualitative), at each concentration level, 22 determinations were made "Within Run," and a "Total Precision" of 88 determinations was reported. However, the total number of unique samples used for the precision study is not explicitly stated. The concentrations were prepared by spiking known amounts of hydrocodone.
- Linearity Studies: For each cutoff, a drug-free urine pool spiked with hydrocodone was serially diluted. Each dilution was run in 10 replicates ("10 replicates on the AU480 instrument"). The total number of unique samples (dilution points) was 12 for the 100 ng/mL cutoff and 11 for the 300 ng/mL cutoff.
- Method Comparison - Clinical Samples: 80 unaltered clinical urine specimens were tested for each cutoff (100 ng/mL and 300 ng/mL).
- Cross-reactivity Studies: Various potentially interfering substances and structurally related/unrelated compounds were tested. The number of unique samples/compounds or replicates for each is not explicitly stated, but the results for each compound are provided.
- Interference (Endogenous, pH, Specific Gravity):
- Endogenous Compound Interference: Various endogenous compounds were tested. Each compound was spiked into a drug-free urine pool, and then split into 3 portions (unspiked, 75/125 ng/mL hydrocodone, or 225/375 ng/mL hydrocodone). The specific number of unique tests for each compound is not explicitly stated beyond these three spiked concentrations.
- pH Interference: Pooled drug-free processed urine samples were adjusted to 9 different target pH values (3-11). Each pH sample was split into 3 portions (unspiked, negative control, positive control). So, 9 x 3 = 27 test conditions for each cutoff.
- Specific Gravity Interference: Ten drug-free urine samples with specific gravity ranging from 1.000 to 1.030 were used. Each sample was split into 3 portions (unspiked, negative control, positive control). So, 10 x 3 = 30 test conditions for each cutoff.
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Data Provenance:
- The document does not explicitly state the country of origin for the clinical samples or for the data collection in general.
- The clinical samples used for the Method Comparison were "unaltered clinical urine specimens," suggesting they were collected from patients. The nature of precision, linearity, cross-reactivity, and interference studies (using spiked drug-free urine or prepared solutions) indicates these were laboratory-based, controlled experiments rather than prospective or retrospective analysis of patient data.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
- For the Method Comparison - Clinical Samples, the ground truth was established by GC/MS or LC/MS. This is an analytical laboratory method, not dependent on human expert interpretation in the same way as, for example, radiological imaging.
- Therefore, the concept of "number of experts" or their "qualifications" for establishing ground truth is not applicable in this context. The accuracy of GC/MS or LC/MS as the confirmatory method itself is assumed.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Since the ground truth for the clinical samples was established by GC/MS or LC/MS, an instrumental analytical method, there was no human adjudication process involved. The result of the GC/MS or LC/MS determined the ground truth directly.
- For the other studies (precision, linearity, cross-reactivity, interference), the ground truth was based on the known concentrations and compositions of the spiked samples.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
- No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done.
- This device is an in-vitro diagnostic assay for drug detection in urine, which does not involve human readers interpreting images or data directly in a clinical decision-making pathway. The device itself performs the detection, and a laboratory professional would interpret the instrument's output. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Yes, the primary performance studies presented are for the LZI Hydrocodone Enzyme Immunoassay operating in a standalone manner. The "LZI Hydrocodone Enzyme Immunoassay" (EIA) itself is the algorithm/device.
- The device provides a "preliminary analytical result" which then requires "a more specific alternative chemical method... GC/MS or LC/MS" for confirmation. While human oversight is always present in a lab setting, the performance data (precision, linearity, clinical sample comparison, cross-reactivity, interference) are solely reflecting the analytical performance of the assay itself on the AU480 analyzer, without direct human-in-the-loop interaction influencing the result generation. The purpose of the semi-quantitative mode is for laboratories to determine appropriate dilution for confirmation, implying the EIA acts as a screening tool.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
- For the Method Comparison study with clinical samples (the most relevant for assessing diagnostic accuracy), the ground truth was established using Gas Chromatography/Mass Spectrometry (GC/MS) or Liquid Chromatography/Mass Spectrometry (LC/MS). These are highly sensitive and specific analytical techniques widely considered the gold standard for drug quantification and confirmation in toxicology.
- For other studies (Precision, Linearity, Cross-reactivity, Interference), the ground truth for the samples was the known concentration/presence of hydrocodone and other substances as prepared by spiking into drug-free urine pools.
8. The sample size for the training set
- The document does not explicitly mention a separate "training set" as would be typical for machine learning algorithms. The LZI Hydrocodone Enzyme Immunoassay is described as a homogeneous enzyme immunoassay kit with liquid reagents, not an AI or machine learning-based device that undergoes a distinct training phase with a dataset.
- The calibrators used to establish reference curves (0, 50, 75, 100, 125, 150, and 300 ng/mL for the 100 ng/mL cutoff; 0, 150, 225, 300, 375, 500, and 800 ng/mL for the 300 ng/mL cutoff) could be considered analogous to training data for the assay, allowing it to quantify hydrocodone based on enzyme activity. However, these are part of the kit's operation, not a separate training phase.
9. How the ground truth for the training set was established
- As mentioned above, the concept of a "training set" in the context of an AI/ML algorithm is not directly applicable to this enzyme immunoassay device.
- The "ground truth" for the calibrators is their known, precisely manufactured concentrations of hydrocodone in human urine. These calibrators are provided as part of the LZI Hydrocodone Enzyme Immunoassay kit and are used to establish the assay's reference curve, which dictates how the instrument interprets enzyme activity into hydrocodone concentration.
§ 862.3650 Opiate test system.
(a)
Identification. An opiate test system is a device intended to measure any of the addictive narcotic pain-relieving opiate drugs in blood, serum, urine, gastric contents, and saliva. An opiate is any natural or synthetic drug that has morphine-like pharmocological actions. The opiates include drugs such as morphine, morphine glucoronide, heroin, codeine, nalorphine, and meperedine. Measurements obtained by this device are used in the diagnosis and treatment of opiate use or overdose and in monitoring the levels of opiate administration to ensure appropriate therapy.(b)
Classification. Class II (special controls). An opiate test system is not exempt if it is intended for any use other than employment or insurance testing or is intended for Federal drug testing programs. The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9, provided the test system is intended for employment and insurance testing and includes a statement in the labeling that the device is intended solely for use in employment and insurance testing, and does not include devices intended for Federal drug testing programs (e.g., programs run by the Substance Abuse and Mental Health Services Administration (SAMHSA), the Department of Transportation (DOT), and the U.S. military).