(29 days)
The LZI Methadone II Enzyme Immunoassay is an in vitro diagnostic test intended for the qualitative and semi-quantitative determination of methadone in human urine. The cutoff for both the qualitative and semi-quantitative modes of the assay is 300 ng/mL for methadone. The assay is designed for prescription use on 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 gas or liquid chromatography/mass spectrometry (GCMS or LC/MS) or (2) permitting laboratories to establish quality control procedures.
The assay provides only a preliminary analytical result. A more specific alternative analytical chemistry 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 Methadone II Enzyme Immunoassay is a homogeneous enzyme immunoassay with ready-to-use liquid reagents. The assay is based on competition between methadone in the sample and methadone 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 methadone concentration in the sample is measured in terms of enzyme activity. In the absence of methadone in the sample, methadone-labeled G6PDH conjugate is bound to antibody, and the enzyme activity is inhibited. On the other hand, when free methadone is present in the sample, antibody would bind to free methadone; the unbound methadone-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 Methadone II 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-methadone 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 methadone in buffer with sodium azide (0.09 %) as a preservative.
The LZI Methadone II Enzyme Immunoassay is an in-vitro diagnostic test for qualitative and semi-quantitative determination of methadone in human urine, with a cutoff of 300 ng/mL. The device's performance was evaluated through various studies demonstrating its precision, linearity, accuracy against LC/MS, cross-reactivity with other substances, and interference from endogenous compounds and pH levels.
Here is a summary of the acceptance criteria and reported device performance from the provided document:
1. Table of Acceptance Criteria and Reported Device Performance
| Device Feature | Acceptance Criteria (Implied / Expected) | Reported Device Performance |
|---|---|---|
| Qualitative Precision | Consistent positive/negative results for samples 25% away from cutoff (e.g., all negative for ≤225 ng/mL, all positive for ≥375 ng/mL). | Within Run (N=22): |
- 0 ng/mL, 75 ng/mL, 150 ng/mL, 225 ng/mL: 22 Negative
- 300 ng/mL: 17 Neg / 5 Pos
- 375 ng/mL, 450 ng/mL, 525 ng/mL, 600 ng/mL: 22 Positive
Total Precision (N=88): - 0 ng/mL, 75 ng/mL, 150 ng/mL, 225 ng/mL: 88 Negative
- 300 ng/mL: 59 Neg / 29 Pos
- 375 ng/mL, 450 ng/mL, 525 ng/mL, 600 ng/mL: 88 Positive |
| Semi-Quantitative Precision | Consistent positive/negative results for samples 25% away from cutoff. | Within Run (N=22): - 0 ng/mL, 75 ng/mL, 150 ng/mL, 225 ng/mL: 22 Negative
- 300 ng/mL: 18 Neg / 4 Pos
- 375 ng/mL, 450 ng/mL, 525 ng/mL, 600 ng/mL: 22 Positive
Total Precision (N=88): - 0 ng/mL, 75 ng/mL, 150 ng/mL, 225 ng/mL: 88 Negative
- 300 ng/mL: 66 Neg / 22 Pos
- 375 ng/mL, 450 ng/mL, 525 ng/mL, 600 ng/mL: 88 Positive |
| Linearity | Recovery values between 85% - 115% of expected values. | Samples from 100 ng/mL to 1000 ng/mL showed recovery ranging from 93.7% to 104.9%. |
| Semi-Quantitative Accuracy (vs. LC/MS) | High percentage agreement with LC/MS results. | % Agreement: 97.8% (Positive), 97.9% (Negative) |
| Qualitative Accuracy (vs. LC/MS) | High percentage agreement with LC/MS results. | % Agreement: 97.8% (Positive), 97.9% (Negative) |
| Cross-reactivity (Structurally Related) | Low cross-reactivity for other methadone-related compounds, and no interference with unrelated compounds. | Methadone: 100.00%
EDDP, EMDP:
§ 862.3620 Methadone test system.
(a)
Identification. A methadone test system is a device intended to measure methadone, an addictive narcotic pain-relieving drug, in serum and urine. Measurements obtained by this device are used in the diagnosis and treatment of methadone use or overdose and to determine compliance with regulations in methadone maintenance treatment.(b)
Classification. Class II (special controls). A methadone 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).