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The Opiate Enzyme Immunoassay is intended for the qualitative and semi-quantitative determination of opiates in human urine, at a cutoff value of 300 ng/mL when calibrated against morphine. The assay is designed for professional 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 or (2) permitting laboratories to establish quality control procedures."

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 liguid 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 Opiate Enzyme Immunoasay is a homogeneous enzyme immunoassay ready-to-use liquid reagent. 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, morphine-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 morphine-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.

Here's a breakdown of the acceptance criteria and study information for the Lin-Zhi International, Inc. Opiate Enzyme Immunoassay, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied by the performance characteristics presented and comparison to the predicate device. The primary performance metrics are precision and agreement with a confirmatory method (GC/MS or LC/MS).

• 0-225 ng/mL: 22 Negative (100%)
• 300 ng/mL: 6 Pos/16 Neg (27.3% Pos, 72.7% Neg)
• 375-600 ng/mL: 22 Positive (100%)
  Total Precision:
• 0-225 ng/mL: 88 Negative (100%)
• 300 ng/mL: 27 Pos/61 Neg (30.7% Pos, 69.3% Neg)
• 375-600 ng/mL: 88 Positive (100%) |
  | Qualitative (mA/min) Detection (Cutoff: 300 ng/mL) | Similar to semi-quantitative qualitative detection. | Within Run:
• 0-225 ng/mL: 22 Negative (100%)
• 300 ng/mL: 16 Pos/6 Neg (72.7% Pos, 27.3% Neg)
• 375-600 ng/mL: 22 Positive (100%)
  Total Precision:
• 0-225 ng/mL: 88 Negative (100%)
• 300 ng/mL: 51 Pos/37 Neg (58.0% Pos, 42.0% Neg)
• 375-600 ng/mL: 88 Positive (100%) |
  | Method Comparison with Confirmatory Method (GC/MS or LC/MS) | High percentage agreement for both positive and negative clinical samples. | Semi-Quantitative Results: 98.3% agreement with positive, 95.9% agreement with negative samples (from 130 clinical samples).
  Qualitative Results: 98.3% agreement with positive, 94.5% agreement with negative samples (from 130 clinical samples). |
  | Limit of Detection (LoD) | Clearly defined lowest detectable concentration. | 20 ng/mL (95% confidence). |
  | Linearity | Strong linear correlation across the analytical range. | 0 - 1000 ng/mL with a regression equation: y = 1.0619x - 2.3861, and r^2 = 0.9976. |
  | Endogenous Compound Interference, Specific Gravity, & Specificity -Cross-Reactivity | No significant undesired cross-reactants or interference from endogenous substances. | "No significant undesired cross reactants or endogenous substance interference was observed." (Refer to product insert for list of compounds tested.) |

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

• Precision Studies: N=88 for each concentration level (0, 75, 150, 225, 300, 375, 450, 525, 600 ng/mL) for both semi-quantitative and qualitative precision analyses. This involved 22 determinations within run and 88 total determinations.
• Method Comparison (Clinical Samples): A total of 130 clinical unaltered samples were used.
• Data Provenance: The document does not explicitly state the country of origin. It indicates that "clinical unaltered samples" were used, suggesting a prospective or collected retrospective real-world dataset. The studies were performed on a Hitachi 717 Analyzer.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

• For the method comparison study, the ground truth was established by a "more specific alternative chemical method," specifically Gas or Liquid Chromatography/Mass Spectrometry (GC/MS or LC/MS). These are instrumental methods, not expert human assessment.
• For the precision and linearity studies, the ground truth concentrations were prepared standard solutions of known concentrations.
• The document does not mention human experts establishing ground truth for any part of the device evaluation.

4. Adjudication Method for the Test Set

Not applicable, as the ground truth was established by objective analytical methods (GC/MS or LC/MS for clinical samples, and known concentrations for precision/linearity studies), not human judgment.

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

Not applicable. This device is an automated in vitro diagnostic (IVD) immunoassay, not an AI-assisted diagnostic tool that involves human readers interpreting images or data. The "readers" are the automated clinical chemistry analyzers.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, the studies presented are all standalone performance studies for the immunoassay. The device itself is an automated system (the immunoassay reagents run on a Hitachi 717 Analyzer) designed to provide results without human interpretation of the primary signal; humans only interpret the final quantitative or qualitative result from the analyzer.

7. The Type of Ground Truth Used

• Method Comparison (Clinical Samples): Gold standard instrumental method, specifically Gas or Liquid Chromatography/Mass Spectrometry (GC/MS or LC/MS).
• Precision, Linearity, LoD: Prepared reference materials with known concentrations of opiates.

8. The Sample Size for the Training Set

Not applicable. This is an immunoassay, not a machine learning or AI algorithm that requires a "training set" in the conventional sense. The "learning" for this type of device involves biochemical interactions and calibration curves, not data-driven model training.

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

Not applicable, as there is no "training set" for an immunoassay. The device relies on its biochemical reaction principles and established calibration against known standards.

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The Opiate Enzyme Immunoassay is a homogeneous enzyme immunoassay with a 300 ng/mL cutoff. The assay is intended for use in the qualitative and semi-quantitative analyses of opiates in human urine.

The Opiate Enzyme Immunoassay 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. Clinical consideration and professional judgement should be applied to any drug-of-abuse test result, particularly when preliminary positive results are used.

LZI's Opiate Enzyme Immunoassay is a ready-to-use, liquid reagent, homogeneous enzyme immunoassay. The assay uses specific antibody that can detect opiates in human urine with minimal cross-reactivity to various, common prescription drugs and abused drugs.

The assay is based on competition between morphine labeled with glucose-6-phosphate dehydrogenase (G6PDH) enzyme, and free drug from the urine sample for a fixed amount of specific antibody. In the absence of free drug from the urine sample the specific antibody binds to the drug labeled with G6PDH enzyme causing a decrease in enzyme activity. The G6PDH enzyme activity is determined spectrophotometrically at 340 nm by measuring its ability to covert nicotinamide adenine dinucleotide (NAD) to NADH.

Here's a breakdown of the acceptance criteria and study information for the Lin-Zhi International, Inc.' Opiate Enzyme Immunoassay, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied by the comparison to the predicate device and the stated "acceptable results." Since this is a 510(k) submission for an in-vitro diagnostic, the primary "acceptance criterion" is often substantial equivalence to a legally marketed predicate. The reported performance of the new device is directly compared to the predicate's performance or presented as standalone performance that is considered acceptable.

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

• Sample Size for Accuracy Test: The accuracy study comparing the LZI device to the DRI® Opiate EIA used n = 216 samples.
• Data Provenance: The document does not specify the country of origin for the data or whether it was retrospective or prospective.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

• Accuracy Study: For the accuracy study against the predicate device, it's not clear that "experts" established a separate ground truth. The comparison was against the results of the DRI® Opiate EIA, which itself is a diagnostic test.
• The predicate device's accuracy was established against GC/MS (Gas Chromatography/Mass Spectrometry), which is typically considered the gold standard for drug quantification. The document does not specify the number or qualifications of experts involved in the GC/MS analysis.

4. Adjudication Method for the Test Set

• The document does not describe any adjudication method (e.g., 2+1, 3+1) for the test set. The comparison for accuracy was directly against the predicate device's results.

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

• No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed. This device is an in-vitro diagnostic test, not an imaging or interpretive AI system that typically involves human readers.

6. Standalone Performance (Algorithm Only Without Human-in-the-Loop Performance)

• Yes, the performance characteristics (precision, sensitivity, accuracy, analytical recovery, interference, specificity) described are for the device (immunoassay) operating in a standalone manner, providing analytical results without human real-time intervention during the analytical process itself. The interpretation of these results for clinical decisions would involve human judgment.

7. Type of Ground Truth Used

• For the LZI device's accuracy study, the "ground truth" was effectively the results from the predicate device (DRI® Opiate EIA).
• For the predicate device, its accuracy was established against GC/MS (Gas Chromatography/Mass Spectrometry), which serves as a definitive analytical "ground truth" for drug levels.

8. Sample Size for the Training Set

• The document does not specify a training set sample size. Immunoassays are not "trained" in the typical machine learning sense with a distinct training dataset. Their performance is inherent in their chemical and biological design. The "studies" described are validation studies (testing) of the final device.

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

• As there is no "training set" in the machine-learning sense for this immunoassay, this question is not applicable. The assay's performance characteristics are determined by its formulation and manufacturing, not by learning from a trained dataset.

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