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An Enzyme Immunoassay for the in vitro diagnostic quantitative measurement of free active testosterone in saliva. Measurement of testosterone is used in the diagnosis and treatment of disorders involving the male sex hormones (androgens), including primary and secondary hypogonadism, delaved or precocious puberty, impotence in males and, in females hirsutism (excessive hair) and virilization (masculinization) due to tumors, polycystic ovaries, and adrenogenital syndromes.

Device Description

The DRG Salivary Testosterone ELISA Kit is based on the competition princible and the microplate separation. An unknown amount of free testosterone present in the sample and a fixed amount of testosterone conjugated with horseradish peroxidase compete for the binding sites of mouse monoclonal testosterone -antiserum coated onto the wells. After one hour incubation the microplate is washed to stop the competition reaction. After addition of the substrate solution the concentration of testosterone is inversely proportional to the optical density measured.

AI/ML Overview

The DRG Salivary Testosterone ELISA is a diagnostic device used for the quantitative measurement of free-active testosterone in saliva. The device performance was evaluated through various studies, including method comparison, sensitivity, specificity, reproducibility, recovery, and linearity.

1. Table of Acceptance Criteria and Reported Device Performance

Performance Metric	Acceptance Criteria (Implicit)	Reported Device Performance
Normal Range	Establish a 5-95% reference range for apparently healthy adult males and females across different age groups.	Determined from 187 adult males (21-75 years) and 188 adult females (21-75 years). Males (pg/mL):- 21-30: 47.2 - 136.2- 31-40: 46.8 - 106.8- 41-50: 36.5 - 82.7- 51-60: 19.1 - 89.0- 61-75: 12.2 - 68.6 Females (pg/mL):- 21-30: 7.9 - 50.4- 31-40: <7.0 - 44.8- 41-50: <7.0 - 39.4- 51-60: <7.0 - 29.8- 61-75: <7.0 - 29.3
Method Comparison	Demonstrate substantial equivalence to a commercially available LIA method for measuring testosterone in saliva, typically indicated by a strong correlation coefficient and acceptable regression analysis. Consistency in reporting is implicitly expected though specific thresholds are not provided.	Study 1: 99 male and female subjects (20-70 years). - Correlation: 0.904 - Regression: y = 0.9251x - 7.4369 (vs LIA)Study 2: 81 additional saliva samples (40-65 year old men and women). - R² = 0.9866- Regression: y = 1.0057x - 2.4196 (DRG ELISA vs LIA)
Sensitivity	The lowest detectable level of testosterone distinguishable from a zero standard (analytical sensitivity) and the lowest functional sensitivity at a specified confidence limit.	- Lowest analytical detectable level: 1.857 pg/mL at 95% confidence limit.- Lowest functional sensitivity: 7.1 pg/mL at 95% confidence limit.
Specificity	Minimal cross-reactivity with other related steroids and compounds, particularly those structurally similar, to ensure accurate testosterone measurement.	- Testosterone: 100%- 5α-Dihydrotestosterone: 0.80%- Androstenedione: 0.90%- 11β-hydroxysterone: 3.30%- 17α-methyltestosterone: 0.10%- 19-Nortestosterone: 3.30%- Epitestosterone: 0.10%- Estradiol: 0.10%- Progesterone: < 0.10%- Cortisol: < 0.10% - Estrone: < 0.10%- Danazol: < 0.10%
Reproducibility	Demonstrate acceptable variability (CV%) for intra-assay (within-run), inter-assay (between-run), and inter-lot (between-kit-lots) measurements across a range of testosterone concentrations. Typically, CV% values should be low, indicating precision.	Intra-Assay (n=20 replicates/sample per run):- CV% range: 6.23% - 13.81% (across 5 samples with mean range 12.94-144.00 pg/mL)Inter-Assay (n=20 duplicate measurements over 10 days/sample):- CV% range: 5.51% - 9.62% (across 5 samples with mean range 33.61-823.08 pg/mL)Inter-Lot (n=9 triplicate measurements over 3 kit lots/sample):- CV% range: 2.90% - 5.85% (across 5 samples with mean range 44.00-517.65 pg/mL)
Recovery	Recover close to 100% of added analyte in spiked samples, demonstrating accuracy and lack of matrix interference. A typical range for acceptable recovery is 90-110%.	Average Recovery: - Range from 92.35% to 104.92% (from 6 saliva samples with various spiked concentrations).Individual Recoveries (selected examples from samples 1-6):- 95.56%, 101.73%, 104.92%, 95.82%- 97.19%, 103.32%, 104.30%, 92.35%- 99.25%, 95.03%, 94.75%, 96.69%- 97.8%, 98.6%, 100.0%- 98.7%, 96.0%, 97.7%- 99.1%, 102.3%, 100.5%
Linearity	Demonstrate that the assay provides proportional results across its claimed analytical measurement range, typically assessed by percentage recovery of serially diluted samples. An acceptable range for recovery is generally 90-110%. The functional range should be clearly defined.	Usable Range: 7.1 - 4500 pg/mL.Average % Recovery: 97.5% - 100.8% (for 6 samples with concentrations from 440.00 to 8000.0 pg/mL).Range of Recovery %: - From 93.6% to 107.8% (across 6 samples). (Three native samples were serially diluted, and 3 samples were spiked and then serially diluted up to 1:128).

2. Sample Sizes Used for the Test Set and Data Provenance:

Normal Range Study: 187 adult male and 188 adult female apparently healthy subjects (ages 21-75 years). Samples were collected in the morning. Data provenance is not explicitly stated beyond "apparently healthy subjects," but given the domestic contact information (New Jersey) and FDA submission, it implicitly refers to data collected within the US or compliant with US regulatory standards. This appears to be a prospective collection for this study.
Method Comparison (Study 1): 99 male and female subjects (ages 20-70 years).
Method Comparison (Study 2): 81 additional saliva samples from 40-65 year old men and women.
Sensitivity: Not specified as a separate test set, derived from standard curve analysis.
Specificity: Not specified as a separate test set, derived from testing specific steroids and compounds.
Reproducibility (Intra-assay): 5 saliva samples, 20 replicate measurements per sample.
Reproducibility (Inter-assay): 5 saliva samples, duplicate measurements over 10 days per sample.
Reproducibility (Inter-lot): 5 saliva samples, triplicate measurements in three different kit lots per sample.
Recovery: 6 different saliva samples.
Linearity: 6 saliva samples (3 native, 3 spiked).

The data provenance for all studies is not explicitly stated but is implicitly within the context of a US-based manufacturer seeking FDA clearance, suggesting data generated for this purpose. The studies described are likely prospective or specifically conducted for the validation of this device.

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

This device is an immunoassay for quantitative measurement. The "ground truth" for such devices often refers to the actual concentration of the analyte, established either by:
* Traceability to recognized reference materials/methods.
* Performance against a well-established, validated comparative method (often called a "predicate" device in regulatory submissions, or a "gold standard" method).

In this context, the "ground truth" for the method comparison studies was established by a "commercially available LIA method" (presumably the predicate device or a reference method). No human experts or their qualifications are mentioned for establishing the ground truth for this type of quantitative assay, as the measurement is chemical/analytical.

4. Adjudication Method for the Test Set:

Not applicable. Adjudication methods (like 2+1, 3+1) are typically used for qualitative or semi-quantitative assessments, especially in imaging or clinical diagnosis where human interpretation is involved. For a quantitative immunoassay like this, the result is a numerical value, and "adjudication" in the traditional sense is not performed. Accuracy is determined by comparing measured values to known concentrations or reference method results.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done:

No, an MRMC comparative effectiveness study was not done. This type of study is typically relevant for diagnostic imaging devices or other tools where human interpretation of results is a critical component and the effect of AI on human reader performance is being evaluated. This device is an automated, quantitative immunoassay.

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

Yes, a standalone study was done. All performance metrics described (Method Comparison, Sensitivity, Specificity, Reproducibility, Recovery, Linearity) represent the performance of the DRG SLV Testosterone ELISA device itself, in an automated or semi-automated laboratory setting, without direct human-in-the-loop interpretation impacting the measurement results.

7. The Type of Ground Truth Used:

The primary ground truth used for performance evaluation was:

Comparative Method: For method comparison studies, the results from a "commercially available LIA method" were used as the reference to assess the DRG device's agreement and substantial equivalence.
Spiked Samples/Known Concentrations: For sensitivity, recovery, and linearity studies, known concentrations of testosterone (either added to samples or derived from serial dilutions) served as the ground truth.
Reference Materials: Implicitly, the sensitivity and specificity characterization would rely on well-characterized reference materials or pure chemical compounds.

8. The Sample Size for the Training Set:

This document describes a diagnostic assay kit (ELISA), not an AI algorithm. Therefore, there is no "training set" in the context of machine learning. The studies described are validation studies to characterize the assay's analytical performance.

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

Not applicable, as there is no "training set" for an ELISA kit. The "ground truth" (i.e., reference values) for the validation studies were established as described in section 7.

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