(267 days)
The Emit® II Plus Cocaine Metabolite Assay is a homogeneous enzyme immunoassay with a 150 ng/mL or 300 ng/mL cutoff. The assay is intended for use in the qualitative and semiquantitative analyses of benzoylecgonine (cocaine metabolite) in human urine. Emit® II Plus assays are designed for use with a number of chemistry analyzers.
The Emit® II Plus Cocaine Metabolite Assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. Other chemical confirmation methods are available. Clinical consideration and professional judgment should be applied to any drug-of-abuse test result, particularly when preliminary positive results are used.
The Emit II Plus Cocaine Metabolite assay is a homogeneous enzyme immunoassay that qualitatively and semiquantitatively measures benzoylecgonine. The assay has cutoffs of 150 ng/mL and 300 ng/mL benzoylecgonine.
The assay is based on competition between drug in the specimen and drug labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for antibody binding sites. Enzyme activity decreases upon binding to the antibody, so the drug concentration in the specimen can be measured in terms of enzyme activity. Active enzyme converts nicotinamide adenine dinucleotide (NAD) to NADH, resulting in an absorbance change that is measured spectrophotometrically at 340 nm.
The Emit II Plus Cocaine Metabolite Assay consists of two ready-to-use reagents:
Antibody/Substrate Reagent 1
Sheep polyclonal antibodies to benzoylecgonine (2.2 µg/mL), bovine serum albumin, G6P (15 mM), NAD (12 mM), preservatives, and stabilizers
Enzyme Reagent 2
Benzoylecgonine labeled with bacterial G6PDH (0.46 U/mL), HEPES buffer, bovine serum albumin, preservatives, and stabilizers
Here's a breakdown of the requested information based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" for the method comparison studies. However, the reported "Result" for agreement percentages can be interpreted as the performance achieved. Similarly, for precision studies, "Results" indicate the number of negative/positive determinations. For linearity, it's % recovery.
Table 1: Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance | Comments |
|---|---|---|---|
| Method Comparison (Qualitative & Semi-Quantitative) | |||
| 150 ng/mL Cutoff | High agreement with GC/MS | 91% agreement | The document does not specify a numerical threshold for "high agreement." |
| 300 ng/mL Cutoff | High agreement with GC/MS | 88% agreement | The document does not specify a numerical threshold for "high agreement." |
| Precision (Qualitative & Semi-Quantitative) | |||
| 150 ng/mL Cutoff | |||
| 0 ng/mL | 100% Negative | 80 Negative | Achieved |
| 38 ng/mL (-75%) | 100% Negative | 80 Negative | Achieved |
| 75 ng/mL (-50%) | 100% Negative | 80 Negative | Achieved |
| 113 ng/mL (-25%) | 100% Negative | 80 Negative | Achieved |
| 150 ng/mL (Cutoff) | Consistent classification (~50% Positive/Negative) | 9 Negative / 71 Positive | At the cutoff, some variability in classification is expected. The exact split for "acceptance" isn't defined but this is a common observation. |
| 188 ng/mL (+25%) | 100% Positive | 80 Positive | Achieved |
| 225 ng/mL (+50%) | 100% Positive | 80 Positive | Achieved |
| 263 ng/mL (+75%) | 100% Positive | 80 Positive | Achieved |
| 300 ng/mL (+100%) | 100% Positive | 80 Positive | Achieved |
| 300 ng/mL Cutoff | |||
| 0 ng/mL | 100% Negative | 80 Negative | Achieved |
| 75 ng/mL (-75%) | 100% Negative | 80 Negative | Achieved |
| 150 ng/mL (-50%) | 100% Negative | 80 Negative | Achieved |
| 225 ng/mL (-25%) | 100% Negative | 80 Negative | Achieved |
| 300 ng/mL (Cutoff) | Consistent classification (~50% Positive/Negative) | 54 Negative / 26 Positive | At the cutoff, some variability in classification is expected. |
| 375 ng/mL (+25%) | 100% Positive | 80 Positive | Achieved |
| 450 ng/mL (+50%) | 100% Positive | 80 Negative (This appears to be an error in the document, should likely be positive) | Note: The document states 80 Negative for +50% of 300 ng/mL cutoff (450 ng/mL) which is contradictory to expectation for a positive result above cutoff. This might be a typo in the provided text. Based on other results, it should be 80 Positive. |
| 525 ng/mL (+75%) | 100% Positive | 80 Positive | Achieved |
| 600 ng/mL (+100%) | 100% Positive | 80 Positive | Achieved |
| Recovery/Linearity (Semiquantitative) | |||
| % Recovery | Not explicitly stated (e.g., ±X%) | Ranges from -0.7% to 8.6% | The document does not specify an acceptance range for % Recovery (e.g., 90-110%). |
| Specificity - Structurally Related Compounds | |||
| Cross-Reactivity | Low cross-reactivity for non-benzoylecgonine compounds | Ecgonine: 2-3%, Cocaine: 0.5%, others |
§ 862.3250 Cocaine and cocaine metabolite test system.
(a)
Identification. A cocaine and cocaine metabolite test system is a device intended to measure cocaine and a cocaine metabolite (benzoylecgonine) in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of cocaine use or overdose.(b)
Classification. Class II (special controls). A cocaine and cocaine metabolite 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).