(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 PositiveTotal 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 PositiveTotal 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: <0.30%Nor-LAAM HCl: 0.40%LAAM HCl: 1.20%Alpha-Methadol: 1.13%Isomethadone HCl: 0.86%Structurally Unrelated Pharmacological Compounds: No significant interference observed for 50+ compounds at high concentrations (100,000 ng/mL, except Duloxetine at 50,000 ng/mL). |
| Endogenous Compound Interference | No significant interference with common endogenous substances at specified concentrations. | Boric Acid: Interference observed at 1% w/v (1000 ng/mL) causing negative results for both 225 ng/mL and 375 ng/mL methadone. No other significant interference observed for the other 12 compounds tested. |
| Specific Gravity Interference | No interference across a range of specific gravity. | No interference observed for samples ranging from 1.003 to 1.028 with and without methadone spikes. |
| pH Interference | No interference across a range of pH levels. | No major interference between pH 3 to pH 11. |
2. Sample Size Used for the Test Set and Data Provenance
- Precision Studies (Qualitative & Semi-quantitative):
- Within Run: 22 data points (2 replicates, 1 run/day for 22 days) for each concentration level (0 ng/mL, 75 ng/mL, 150 ng/mL, 225 ng/mL, 300 ng/mL, 375 ng/mL, 450 ng/mL, 525 ng/mL, 600 ng/mL).
- Total Precision: 88 data points (2 replicates, 2 runs/day for 22 days) for each concentration level.
- Provenance: Samples were prepared by spiking a methadone standard into a pool of negative human urine. Therefore, this data is from controlled laboratory conditions, not directly from patients.
- Method Comparison - Clinical Samples (Accuracy Study):
- Sample Size: A total of ninety-four (94) unaltered clinical samples.
- Provenance: Samples were collected by Lin-Zhi International, Inc. (LZI) and from the University of California, San Francisco (UCSF). This indicates human clinical data.
- Linearity: Serially diluted methadone spiked urine, each run in 10 replicates for a range of 0 to 1000 ng/mL.
- Cross-reactivity and Endogenous Compound Interference: Various concentrations of each substance spiked into pooled negative human urine. (Not specified if replicates were performed for all, but for structurally unrelated compounds, it states "All samples were tested in replicates.")
- Specific Gravity and pH Interference: Urine samples (negative and spiked with methadone) adjusted to different specific gravity and pH levels respectively.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not explicitly state the number or qualifications of experts used to establish ground truth.
For the accuracy studies with clinical samples, the ground truth was established by LC/MS (Liquid Chromatography/Mass Spectrometry), which is an independent and highly sensitive analytical chemistry method. This method itself acts as the "gold standard" or "ground truth" for drug concentration determination, rather than relying on human expert interpretation of the test results.
4. Adjudication Method for the Test Set
Not applicable. The ground truth for concentrations (precision, linearity, cross-reactivity, interference studies) was determined analytically. For clinical samples, the ground truth for methadone concentration was established by LC/MS, acting as an objective reference standard. No human adjudication process involving multiple readers is described for the test results.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC comparative effectiveness study was not done. This device is an in-vitro diagnostic assay for chemical analysis, not an imaging device or AI diagnostic tool that typically involves human reader interpretation. Therefore, the concept of human readers improving with or without AI assistance is not relevant here.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
Yes, the studies presented are all standalone performance evaluations of the LZI Methadone II Enzyme Immunoassay device itself, without human interpretation in the results. The device outputs a quantitative or qualitative result, which is then compared against established ground truths (e.g., LC/MS, spiked concentrations).
7. The Type of Ground Truth Used
- For Precision, Linearity, Cross-reactivity, and Interference Studies: The ground truth was established by preparing urine samples with known, spiked concentrations of methadone or other compounds.
- For Method Comparison (Accuracy) with Clinical Samples: The ground truth for methadone and methadone metabolite concentrations was established using LC/MS (Liquid Chromatography/Mass Spectrometry).
8. The Sample Size for the Training Set
The document describes performance studies, which represent a test set. It does not mention a specific "training set" or "validation set" in the context of an algorithm or machine learning. For an immunoassay, the "training" typically refers to the assay development and optimization process, not a separate data set in the same way as an AI model.
9. How the Ground Truth for the Training Set Was Established
As noted above, the concept of a "training set" for an algorithm with specific ground truth establishment is not directly applicable to this immunoassay device in the provided document. The development and optimization of the immunoassay (analogous to "training" in AI) would involve establishing reactivity to methadone and minimal cross-reactivity via laboratory experiments and chemical principles, rather than a distinct training data set with ground truth in the AI sense.
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October 4, 2019
Lin-Zhi International, Inc Bernice Lin VP Operations 2945 Oakmead Village Court Santa Clara, CA 95051
Re: K192433
Trade/Device Name: LZI Methadone II Enzyme Immunoassay Regulation Number: 21 CFR 862.3620 Regulation Name: Methadone test system Regulatory Class: Class II Product Code: DJR Dated: August 30, 2019 Received: September 5, 2019
Dear Bernice Lin:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal
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statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
Kellie B. Kelm, Ph.D. Acting Director Division of Chemistry and Toxicology Devices OHT7: Office of In Vitro Diagnostics and Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K192433
Device Name LZI Methadone II Enzyme Immunoassay
Indications for Use (Describe)
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.
Type of Use (Select one or both, as applicable)
| Prescription Use (Part 21 CFR 801 Subpart D) | |
|---|---|
| Over-The-Counter Use (21 CFR 801 Subpart C) |
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510(k) Summary of Safety and Effectiveness
This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.
Submitted On
August 30, 2019
Last Updated On
October 3, 2019
Introduction
According to the requirements of 21 CFR 807.92, the following information provides sufficient detail to understand the basis for a determination of substantial equivalence.
Submitter Name, Address, and Contact:
Lin-Zhi International, Inc. 2945 Oakmead Village Court Santa Clara, CA 95051 Phone: (408) 970-8811 Fax: (408) 970-9030 e-mail: bclin@lin-zhi.com
| Contact: | Bernice Lin, Ph.D. |
|---|---|
| VP Operations |
Device Name and Classification
| Classification Name: | Enzyme Immunoassay, MethadoneClass II, DJR (91 Toxicology),21 CFR 862.3620 |
|---|---|
| Common Name: | Homogeneous Methadone Enzyme Immunoassay |
| Proprietary Name: | LZI Methadone II Enzyme Immunoassay |
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Legally Marketed Predicate Device(s)
The LZI Methadone II Enzyme Immunoassay (EIA) is substantially equivalent to the Methadone Enzyme Immunoassay (K023317) manufactured by Lin-Zhi International, Inc. The LZI Methadone II Enzyme Immunoassay is identical or similar to its predicate in terms of intended use, method principle, device components, and clinical performance.
Device Description
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.
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Intended Use
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 (GC/MS 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 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.
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Comparison to Predicate Device
The LZI Methadone II Enzyme Immunoassay is substantially equivalent to the Lin-Zhi International, Inc. Methadone Enzyme Immunoassay, Calibrators, and Controls for Hitachi systems cleared by the FDA under the premarket notification K023317 for their stated intended use.
The following table compares the LZI Methadone II Enzyme Immunoassay with the predicate device.
| DeviceCharacteristics | Subject Device | Predicate Device (K023317) |
|---|---|---|
| Intended Use | The LZI Methadone II Enzyme ImmunoassayThe LZI Methadone II EnzymeImmunoassay is an in vitro diagnostic testintended for the qualitative andsemi-quantitative determination ofmethadone in human urine. The cutoff forthe qualitative and semi-quantitativemodes of the assay is 300 ng/mL formethadone. The assay is designed forprescription use on automated clinicalchemistry analyzers.The semi-quantitative mode is forpurposes of (1) enabling laboratories todetermine an appropriate dilution of thespecimen for confirmation by aconfirmatory method such as gas or liquidchromatography/mass spectrometry(GC/MS or LC/MS) or (2) permittinglaboratories to establish quality controlprocedures.The assay provides only a preliminary analyticalresult. A more specific alternative analyticalchemistry method must be used in order to obtain aconfirmed analytical result. Gas or liquidchromatography/mass spectrometry (GC/MS orLC/MS) is the preferred confirmatory method.Clinical consideration and professional judgmentshould be exercised with any drug of abuse testresult, particularly when the preliminary test resultis positive. | Methadone Enzyme ImmunoassayThe Lin-Zhi International, Inc. (LZI)Methadone Enzyme Immunoassay isintended for the qualitative andsemi-quantitative determination ofmethadone in human urine at a cutoff valueof 300 ng/mL. The assay is designed forprofessional use with a number ofautomated clinical chemistry analyzers.This assay provides a rapid screening procedurefor determining the presence of methadonemetabolite in urine. The assay provides only apreliminary analytical result. A more specificalternative chemical method must be used in orderto obtain a confirmed analytical result. Gas orliquid chromatography/mass spectrometry (GC/MSor LC/MS) is the preferred confirmatory method.Clinical consideration and professional judgmentshould be exercised with any drug of abuse testresult, particularly when the preliminary test resultis positive. |
| Analyte | methadone | methadone |
| Cutoff | 300 ng/mL | 300 ng/mL |
| Matrix | urine | urine |
| Calibrators Level | 0, 150, 300, 600, and 1000 ng/mL | 0, 150, 300, 600, and 1000 ng/mL |
| Controls Level | 225 ng/mL and 375 ng/mL | 225 ng/mL and 375 ng/mL |
| Storage | 2-8°C until expiration date | 2-8°C until expiration date |
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Performance Characteristics Summary: Beckman Coulter® AU680 Analyzer
Precision
The assay tested in qualitative (△OD, mAU) and semi-quantitative (ng/mL) mode using a modified NCCLS-EP5 protocol. Methadone sample concentrations were prepared by spiking a methadone standard into a pool of negative human urine at concentrations ±25%, ±50%, ±75%, and ±100% of cutoff concentration.
Results shown below were obtained by testing all samples in replicate of two, two runs a day (one in the morning and one in the afternoon) for 22 days on one AU680 automatic clinical analyzer for a total of 88 runs. Samples were evaluated against the assay's calibration curve in both qualitative and semi-quantitative modes. One single lot of reagents, calibrators, and controls were used and stored at 2-8℃ when not in use.
| MethadoneConcentration | Within Run (N=22)QualitativeResponse | Total Precision (N=88)Qualitative Response |
|---|---|---|
| 0 ng/mL | - | - |
| 75 ng/mL | - | - |
| 150 ng/mL | - | - |
| 225 ng/mL | - | - |
| 300 ng/mL | - | - |
| 375 ng/mL | + | + |
| 450 ng/mL | + | + |
| 525 ng/mL | + | + |
| 600 ng/mL | + | + |
Semi-Quantitative Precision Analysis Summary: Qualitative Results
| Semi-Quantitative Positive/Negative Results: | ||
|---|---|---|
| 300 ng/mL Cutoff Result: | Within Run (N=22) | Total Precision (N=88) | |||
|---|---|---|---|---|---|
| MethadoneConcentration | % of Cutoff | # of Samples | EIA Result | # of Samples | EIA Result |
| 0 ng/mL | 0.0% | 22 | 22 Negative | 88 | 88 Negative |
| 75 ng/mL | 25.0% | 22 | 22 Negative | 88 | 88 Negative |
| 150 ng/mL | 50.0% | 22 | 22 Negative | 88 | 88 Negative |
| 225 ng/mL | 75.0% | 22 | 22 Negative | 88 | 88 Negative |
| 300 ng/mL | 100.0% | 22 | 18 Neg/4 Pos | 88 | 66 Neg/22 Pos |
| 375 ng/mL | 125.0% | 22 | 22 Positive | 88 | 88 Positive |
| 450 ng/mL | 150.0% | 22 | 22 Positive | 88 | 88 Positive |
| 525 ng/mL | 175.0% | 22 | 22 Positive | 88 | 88 Positive |
| 600 ng/mL | 200.0% | 22 | 22 Positive | 88 | 88 Positive |
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Performance Characteristics Summary, continued:
Beckman Coulter® AU680 Analyzer
| 300 ng/mL Cutoff Result: | Within Run (N=22) | Total Precision (N=88) | |||
|---|---|---|---|---|---|
| MethadoneConcentration | % of Cutoff | # of Samples | EIA Result | # of Samples | EIA Result |
| 0 ng/mL | 0.0 % | 22 | 22 Negative | 88 | 88 Negative |
| 75 ng/mL | 25.0 % | 22 | 22 Negative | 88 | 88 Negative |
| 150 ng/mL | 50.0 % | 22 | 22 Negative | 88 | 88 Negative |
| 225 ng/mL | 75.0 % | 22 | 22 Negative | 88 | 88 Negative |
| 300 ng/mL | 100.0 % | 22 | 17 Neg/ 5 Pos | 88 | 59 Neg/29 Pos |
| 375 ng/mL | 125.0 % | 22 | 22 Positive | 88 | 88 Positive |
| 450 ng/mL | 150.0 % | 22 | 22 Positive | 88 | 88 Positive |
| 525 ng/mL | 175.0 % | 22 | 22 Positive | 88 | 88 Positive |
| 600 ng/mL | 200.0 % | 22 | 22 Positive | 88 | 88 Positive |
Qualitative Positive/Negative Results:
Linearity
To demonstrate linearity of the entire assay range, a drug free-urine pool spiked with methadone at 1000 ng/mL was serially diluted. Each sample was run in 10 replicates and the average was used to determine percent recovery compared to the expected target value.
Observed values were obtained and acceptable if measurements were ±15% of the expected values. Recovery values (Expected Value divided by the Observed Value) were considered acceptable between 85 - 115%.
Samples from the linear range of the assay (100 ng/mL to 1000 ng/mL) were tested with recovery ranging from 93.7% to 104.9%.
| Expected Value(ng/mL) | Observed Value(ng/mL) | % Recovery |
|---|---|---|
| 1000 | 950.5 | 95.0% |
| 900 | 848.6 | 94.3% |
| 800 | 767.9 | 96.0% |
| 700 | 668.0 | 95.4% |
| 600 | 572.2 | 95.4% |
| 500 | 463.0 | 92.6% |
| 400 | 393.4 | 98.4% |
| 300 | 287.8 | 95.9% |
| 200 | 187.4 | 93.7% |
| 100 | 104.9 | 104.9% |
| 20 | 15.8 | 78.9% |
| 0 | -7.1 | N/A |
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Method Comparison - Clinical Samples
A total of ninety-four (94) unaltered clinical samples were tested with the LZI Methadone II Enzyme Immunoassay on the Beckman Coulter® AU680 automated clinical analyzer. Samples were evaluated against the assay's calibration curve in both qualitative and semi-quantitative modes. All samples were tested in singlet.
All samples were confirmed with LC/MS for both methadone and methadone metabolite concentrations. Samples were collected by Lin-Zhi International, Inc. (LZI) and from the University of California, San Francisco (UCSF).
Semi-Quantitative Accuracy Study
Discrepant samples determined as compared to methadone concentration from LC/MS.
| CandidateDeviceResults | Negative | <50 %ofCutoff | Near CutoffNegative(between -50% of cutoffto the cutoff) | Near CutoffPositive(between cutoffand +50 % ofcutoff) | HighPositive(>50 %abovecutoff) | %Agreement |
|---|---|---|---|---|---|---|
| Positive | 0 | 0 | 1* | 4 | 41 | 97.8 % |
| Negative | 20 | 23 | 4 | 1** | 0 | 97.9 % |
| Sample# | LC/MSMethadone(ng/mL) | Pos/NegResult | AU680 EIAPos/NegResult |
|---|---|---|---|
| 48* | 274 | - | + |
| 50** | 317 | + | - |
- Discrepant between 50% below cutoff and cutoff concentration (150 – 299,9 ng/mL)
** Discrepant between cutoff and 50% above cutoff concentration (300 - 449.9 ng/mL)
Qualitative Accuracy Study
| CandidateDeviceResults | Negative | <50 %ofCutoff | Near CutoffNegative(between -50% of cutoffto the cutoff) | Near CutoffPositive(between cutoffand +50 % ofcutoff) | HighPositive(>50 %abovecutoff) | %Agreement |
|---|---|---|---|---|---|---|
| Positive | 0 | 0 | 1* | 4 | 44 | 97.8 % |
| Negative | 20 | 23 | 4 | 1** | 0 | 97.9 % |
| Sample# | LC/MSMethadone(ng/mL) | Pos/NegResult | AU680 EIAQualitativeResult (mAU) | Pos/NegResult | QualitativeCutoff Rate(mAU) |
|---|---|---|---|---|---|
| 48* | 274 | - | 176.5 | + | 133.5 |
| 50** | 317 | + | 95.4 | - | 165.0 |
- Discrepant between 50% below cutoff and cutoff concentration (150 - 299.9 ng/mL)
** Discrepant between cutoff and 50% above cutoff concentration (300 - 449.9 ng/mL)
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Cross-reactivity
The Cross-reactivity of various potentially interfering drugs were tested by spiking various concentrations of each substance into a pool of negative human urine and then evaluated against the assay's calibration curve in both qualitative and semi-quantitative modes. All samples were tested in replicates.
The table below lists the concentration of each test compound that gave a response approximately equivalent to that of the cutoff calibrator (as positive) or the maximal concentration of the compound tested that gave a response below the response of the cutoff calibrator (as negative). Compounds tested at high concentration with results below the cutoff value were listed as Not Detected (ND).
| Compound | TargetConcentration(ng/mL) | % Cross-reactivity |
|---|---|---|
| Methadone | 300 | 100.00% |
| EDDP | 100,000 | <0.30% |
| EMDP | 100,000 | <0.30% |
| (-)-α-Noracetylmethadol(Nor-LAAM) HCl | 75,000 | 0.40% |
| LAAM HCl | 25,000 | 1.20% |
| (±)-α-Methadol | 26,500 | 1.13% |
| (-)-Isomethadone HCl | 35,000 | 0.86% |
Methadone and Structurally Related Compounds:
Structurally unrelated compounds were additionally spiked into pooled negative human urine to desired concentrations (as described above). These solutions were then split into three portions; one without methadone, and the remaining two that were further spiked with methadone standards to a final methadone concentration of 225 ng/mL (as negative or positive controls, ±25% cutoff concentration, respectively). Samples were then evaluated against the assay's calibration curve in both qualitative and semi-quantitative modes. All samples were tested in replicates.
Structurally Unrelated Pharmacological Compounds:
| Spiked [ ](ng/mL) | Spiked Methadone Concentration | |||
|---|---|---|---|---|
| Cross-reactant | 0 ng/mL | 225 ng/mLControl | 375 ng/mLControl | |
| Acetaminophen | 100,000 | ND | Neg | Pos |
| 6-Acetylmorphine | 100,000 | ND | Neg | Pos |
| Acetylsalicylic Acid | 100,000 | ND | Neg | Pos |
| Amitriptyline | 100,000 | ND | Neg | Pos |
| Amlodipine Besylate | 100,000 | ND | Neg | Pos |
| Amoxicillin | 100,000 | ND | Neg | Pos |
| d-Amphetamine | 100,000 | ND | Neg | Pos |
| Atorvastatin | 100,000 | ND | Neg | Pos |
| Acetaminophen | 100,000 | ND | Neg | Pos |
| 6-Acetylmorphine | 100,000 | ND | Neg | Pos |
| Cross-reactant | Spiked [] (ng/mL) | 0 ng/mL | 225 ng/mL Control | 375 ng/mL Control |
| Acetylsalicylic Acid | 100,000 | ND | Neg | Pos |
| Amitriptyline | 100,000 | ND | Neg | Pos |
| Amlodipine Besylate | 100,000 | ND | Neg | Pos |
| Amoxicillin | 100,000 | ND | Neg | Pos |
| d-Amphetamine | 100,000 | ND | Neg | Pos |
| Atorvastatin | 100,000 | ND | Neg | Pos |
| Benzoylecgonine | 100,000 | ND | Neg | Pos |
| Buprenorphine | 100,000 | ND | Neg | Pos |
| Bupropion | 100,000 | ND | Neg | Pos |
| Caffeine | 100,000 | ND | Neg | Pos |
| Carbamazepine | 100,000 | ND | Neg | Pos |
| Cetirizine | 100,000 | ND | Neg | Pos |
| Chlorpheniramine | 100,000 | ND | Neg | Pos |
| Chlorpromazine | 100,000 | ND | Neg | Pos |
| Clomipramine | 100,000 | ND | Neg | Pos |
| Codeine | 100,000 | ND | Neg | Pos |
| Desipramine | 100,000 | ND | Neg | Pos |
| Diphenhydramine | 100,000 | ND | Neg | Pos |
| Duloxetine | 50,000 | ND | Neg | Pos |
| Fentanyl | 100,000 | ND | Neg | Pos |
| Fluoxetine | 100,000 | ND | Neg | Pos |
| Fluphenazine | 100,000 | ND | Neg | Pos |
| Gabapentin | 100,000 | ND | Neg | Pos |
| Hydrocodone | 100,000 | ND | Neg | Pos |
| Hydromorphone | 100,000 | ND | Neg | Pos |
| Ibuprofen | 100,000 | ND | Neg | Pos |
| Imipramine | 100,000 | ND | Neg | Pos |
| Lisinopril | 100,000 | ND | Neg | Pos |
| Losartan | 100,000 | ND | Neg | Pos |
| Loratidine | 100,000 | ND | Neg | Pos |
| MDA (3,4-methylenedioxy-amphetamine) | 100,000 | ND | Neg | Pos |
| MDEA | 100,000 | ND | Neg | Pos |
| MDMA (3,4-methylenedioxy-methamphetamine) | 100,000 | ND | Neg | Pos |
| Meperidine | 100,000 | ND | Neg | Pos |
| Metformin | 100,000 | ND | Neg | Pos |
| Metoprolol | 100,000 | ND | Neg | Pos |
| d-Methamphetamine | 100,000 | ND | Neg | Pos |
| Morphine | 100,000 | ND | Neg | Pos |
| Nicotine | 100,000 | ND | Neg | Pos |
| Nortriptyline | 100,000 | ND | Neg | Pos |
| Omeprazole | 100,000 | ND | Neg | Pos |
| Cross-reactant | Spiked [ ] (ng/mL) | Spiked Methadone Concentration | ||
| 0 ng/mL | 225 ng/mL Control | 375 ng/mL Control | ||
| Oxazepam | 100,000 | ND | Neg | Pos |
| Oxycodone | 100,000 | ND | Neg | Pos |
| Oxymorphone | 100,000 | ND | Neg | Pos |
| Phenobarbital | 100,000 | ND | Neg | Pos |
| (1S,2S)-(+)Pseudoephedrine | 100,000 | ND | Neg | Pos |
| Quetiapine | 100,000 | ND | Neg | Pos |
| Ranitidine | 100,000 | ND | Neg | Pos |
| Salbutamol (Albuterol) | 100,000 | ND | Neg | Pos |
| Sertraline | 100,000 | ND | Neg | Pos |
| THC-COOH(11-Nor-Delta-9-THC-9-carboxylic acid) | 100,000 | ND | Neg | Pos |
| L-Thyroxine | 100,000 | ND | Neg | Pos |
| Tramadol | 100,000 | ND | Neg | Pos |
| Zolpidem | 100,000 | ND | Neg | Pos |
{11}------------------------------------------------
Structurally Unrelated Pharmacological Compounds, continued:
{12}------------------------------------------------
Structurally Unrelated Pharmacological Compounds, continued:
Endogenous Compound Interference:
Endogenous compounds were spiked into pooled negative human urine to desired concentrations. These solutions were then split into three portions; one without methadone, and the remaining two that were further spiked with methadone standards to a final methadone concentration of 225 ng/mL or 375 ng/mL (as negative or positive controls,
±25% cutoff concentration, respectively). Samples were then evaluated against the assay's calibration curve in both qualitative and semi-quantitative modes. All samples were tested in replicates.
| Endogenous Substance | ConcentrationTested (ng/mL) | Spiked Methadone Concentration | ||
|---|---|---|---|---|
| 0 ng/mL | 225 ng/mLControl | 375 ng/mLControl | ||
| Acetone | 1000 | Neg | Neg | Pos |
| Ascorbic Acid | 1500 | Neg | Neg | Pos |
| Bilirubin | 2 | Neg | Neg | Pos |
| Boric Acid* | 1000 | Neg | Neg | Neg |
| Calcium Chloride(CaCl2) | 300 | Neg | Neg | Pos |
| Citric Acid (pH 3) | 800 | Neg | Neg | Pos |
| Creatinine | 500 | Neg | Neg | Pos |
| Ethanol | 1000 | Neg | Neg | Pos |
| Galactose | 10 | Neg | Neg | Pos |
| y-Globulin | 500 | Neg | Neg | Pos |
| Glucose | 3000 | Neg | Neg | Pos |
| Hemoglobin | 300 | Neg | Neg | Pos |
| β-hydroxybutyric Acid | 100 | Neg | Neg | Pos |
| HSA | 500 | Neg | Neg | Pos |
{13}------------------------------------------------
| Endogenous Substance | ConcentrationTested (ng/mL) | Spiked Methadone Concentration | ||
|---|---|---|---|---|
| 0 ng/mL | 225 ng/mLControl | 375 ng/mLControl | ||
| Oxalic Acid | 100 | Neg | Neg | Pos |
| Potassium Chloride* | 6000 | Neg | Neg | Neg |
| Riboflavin | 0.3 | Neg | Neg | Pos |
| Urea | 6000 | Neg | Neg | Pos |
| Uric Acid | 10 | Neg | Neg | Pos |
| Sodium Azide | 1000 | Neg | Neg | Pos |
| Sodium Chloride | 1000 | Neg | Neg | Pos |
| Sodium Fluoride | 1000 | Neg | Neg | Pos |
| Sodium Phosphate | 300 | Neg | Neg | Pos |
Endogenous Compound Interference, continued:
The following endogenous compounds which showed interference at ±25 % of cutoff concentrations were then spiked into negative urine and at ±50 % of cutoff concentrations (150 ng/mL and 450 ng/mL) for the assay.
Interference was observed with Boric Acid at 1 % w/v. No other significant undesired crossreactants or endogenous substance interference was observed.
| Endogenous Substance | ConcentrationTested (ng/mL) | Spiked Methadone Concentration | ||
|---|---|---|---|---|
| 0 ng/mL | 150 ng/mLControl | 450 ng/mLControl | ||
| Boric Acid | 1000 | Neg | Neg | Neg |
| Potassium Chloride | 6000 | Neg | Neg | Pos |
Specific Gravity:
Samples ranging in specific gravity from 1.003 to 1.028 were split into three portions each and either left un-spiked or further spiked to a final methadone concentration of either 225 ng/mL or 375 ng/mL (the negative and positive control concentrations, respectively). These samples were then evaluated in qualitative mode. No interference was observed.
{14}------------------------------------------------
pH Interference Study:
Negative urine and urine spiked with methadone to the final methadone concentration of either 225 ng/mL or 375 ng/mL (the negative and positive control concentrations, respectively) were adjusted to the following pH levels and tested by the assay. The pH adjusted solutions were evaluated against the cutoff calibrator.
| pH | Spiked Methadone Concentration | ||
|---|---|---|---|
| 0 ng/mL | 225 ng/mL Control | 375 ng/mL Control | |
| pH 3 | Neg | Neg | Pos |
| pH 4 | Neg | Neg | Pos |
| pH 5 | Neg | Neg | Pos |
| pH 6 | Neg | Neg | Pos |
| pH 7 | Neg | Neg | Pos |
| pH 8 | Neg | Neg | Pos |
| pH 9 | Neg | Neg | Pos |
| pH 10 | Neg | Neg | Pos |
| pH 11 | Neg | Neg | Pos |
No major interference between pH 3 to pH 11. Results are summarized in the following table:
Summary:
The information provided in this pre-market notification demonstrates that the LZI Methadone II Enzyme Immunoassay is substantially equivalent to the legally marketed predicate device for its general intended use. Substantial equivalence was demonstrated through comparison of intended use and physical properties to the commercially available predicate device as confirmed by chromatography/mass spectrometry (LC/MS), an independent analytical chemistry method. The information supplied in this pre-market notification provides reasonable assurance that the LZI Methadone II Enzyme Immunoassay is safe and effective for its stated intended use.
§ 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).