(241 days)
The Access SHBG assay is a paramagnetic particle, chemiluminescent immunoassay for the quantitative determination of Sex Hormone Binding Globulin levels in human serum and plasma using the Access Immunoassay Systems. The Access Sex Hormone Binding Globulin assay is indicated for use in the assessment of androgen disorders.
The Access SHBG Calibrators are intended to calibrate the Access SHBG assay for the quantitative determination of Sex Hormone Binding Globulin levels in human serum and plasma using the Access Immunoassay Systems.
The Access SHBG QC is intended for monitoring system performance of the Access SHBG assay.
The Access SHBG assay is a sequential two-step immunoenzymatic ("sandwich") assay. A sample is added to a reaction vessel along with paramagnetic particles coated with anti-SHBG antibody. During incubation, the SHBG antigen in the sample binds to the immobilized anti-SHBG antibody on the solid phase. Alkaline phosphatase conjugated anti-SHBG antibody is then added and reacts with a different antigenic site on the SHBG molecule. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate Lumi-Phos 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of SHBG in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.
Here's a breakdown of the acceptance criteria and the study information for the Access SHBG device, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criteria | Reported Device Performance (Access SHBG) |
|---|---|
| Imprecision (Total CV%) | ** 2 nmol/L** |
- Sample 1 (6.3 nmol/L): Total CV 5.4%
- Sample 2 (38 nmol/L): Total CV 5.3%
- Sample 3 (80 nmol/L): Total CV 5.5%
- Sample 4 (171 nmol/L): Total CV 5.2%
Estimated CV% based on polynomial regression across the assay range (2-180 nmol/L) is 5.3%. |
| Analytical Sensitivity (Limit of Blank - LoB) | 0.017 nmol/L |
| Analytical Sensitivity (Limit of Detection - LoD) | 0.33 nmol/L |
| Dilution Recovery (Linearity) | Sample 1 (206.58 nmol/L): 103% Mean Recovery
Sample 2 (35.81 nmol/L): 101% Mean Recovery
Sample 3 (2.90 nmol/L): 100% Mean Recovery |
| Method Comparison (Correlation to Predicate Device) | Correlation Coefficient (r²) = 0.94 (between Access SHBG and DPC Immulite SHBG) |
| Interference | No significant interference from tested compounds including triglycerides, protein, bilirubin, cortisol, hemoglobin, estradiol, testosterone, 5α-DHT, 11-Deoxycortisol, acetaminophen, acetylsalicylic acid, alpha-fetoprotein (AFP), heparin, ibuprofen, GAS6, laminin, multivitamin supplement, thyroglobulin (Tg), thyroxine-binding globulin (TBG), transferrin at relevant levels. |
| Cross-Reactivity | No significant cross-reactivity with 5a-dihydroxytestosterone, 11-deoxycotrisol, estradiol, GAS6, laminin, protein S, testosterone, alpha-fetoprotein, thyroglobulin, thyroxine-binding globulin, and transferrin. |
| Stability (Reagents, Calibrators, Controls) | 28 days after opening |
| Stability (Calibration Curve) | 28 days |
Study Information:
2. Sample Size Used for the Test Set and Data Provenance:
- Imprecision Study: Four patient samples at varying SHBG levels were used. The study involved running these samples for 20 different days, completing 2 runs per day, resulting in 480 data points (n=480) for the mean calculation.
- Analytical Sensitivity (LoB & LoD): Specific sample numbers are not provided, but the statement indicates "lowest level sample where the beta-percentile (...) was 5% or less" was used for LoD, and LoB used a 97.5% upper confidence limit.
- Dilution Recovery: Three serum samples were used (206.58 nmol/L, 35.81 nmol/L, and 2.90 nmol/L).
- Methods Comparison: 158 values (samples or observations) were used. The range of observations was 5.7-184.5 nmol/L. The data provenance is not explicitly stated in terms of country of origin but implies human serum from "patient samples." It is implied to be prospective as it's a comparison of a new device against an existing one, likely conducted as part of the validation.
- Interferences & Cross-Reactivity: Not explicitly stated, but derived from studies based on CLSI EP7-A2 guidance, which typically involve spiking known interferents into patient or control samples.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:
- This device is an in vitro diagnostic (IVD) immunoassay for quantitative determination of SHBG levels. The "ground truth" for such devices is typically established through reference methods, established predicate devices, or calibrated reference materials, not through expert consensus in the way a diagnostic imaging device would use radiologists. The methods comparison study used a "commercially available enzyme immunoassay system" (the DPC Immulite SHBG) as a comparator, which itself has an established analytical performance. No human experts are explicitly mentioned as establishing ground truth in this context.
4. Adjudication Method for the Test Set:
- Not applicable in the traditional sense for an immunoassay. Discrepancies in results would be investigated through re-testing, calibration checks, or instrument troubleshooting, rather than human expert adjudication of a diagnostic finding.
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 immunoassay for quantitative chemical analysis, not an AI-assisted diagnostic imaging or interpretation tool that would involve human readers.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
- This is a standalone device in the sense that it performs automated quantitative measurements. There is no "human-in-the-loop" for the direct measurement itself; the human interacts with the system by placing samples and interpreting the numerical results. The performance data presented (imprecision, sensitivity, linearity, method comparison) are inherently "standalone" performance metrics of the device.
7. The Type of Ground Truth Used:
- The ground truth for the method comparison study was established by the predicate device (DPC Immulite SHBG assay).
- For other analytical performance studies (imprecision, sensitivity, linearity, interference, cross-reactivity), the ground truth is established by known concentrations in control materials, spiked samples, or reference standards, based on established laboratory practices and CLSI guidelines.
8. The Sample Size for the Training Set:
- Not applicable for this type of immunoassay. These devices are typically developed and validated using analytical studies rather than machine learning "training sets." The calibration curve is established using calibrators with known concentrations, which are analogous to a very small "training set" for the device's internal measurement algorithm, but not in the sense of a large machine learning dataset. Five calibrator levels (S1-S5) plus S0 are used to establish the calibration curve.
9. How the Ground Truth for the Training Set Was Established:
- The "ground truth" for the calibrators (S1-S5) is established by using purified human SHBG at known concentrations, traced to the WHO 95/560 standard. This ensures accuracy and traceability of the quantitative measurements.
§ 862.1680 Testosterone test system.
(a)
Identification. A testosterone test system is a device intended to measure testosterone (a male sex hormone) in serum, plasma, and urine. Measurement of testosterone are used in the diagnosis and treatment of disorders involving the male sex hormones (androgens), including primary and secondary hypogonadism, delayed or precocious puberty, impotence in males and, in females hirsutism (excessive hair) and virilization (masculinization) due to tumors, polycystic ovaries, and adrenogenital syndromes.(b)
Classification. Class I.