(123 days)
The Focus Diagnostics Plexus™ HerpeSelect® HSV 1 and 2 IgG (with software) is intended for qualitatively detecting the presence or absence of human IgG antibodies to HSV-1 and HSV-2 in human sera. The test is indicated for pregnant women and sexually active adults, as an aid for presumptively diagnosing HSV-1 and HSV-2 infection. The predictive value of a positive or negative result depends on the population's prevalence and the pretest likelihood of HSV-1 and HSV-2 infection. The test is not intended for donor screening or for self-testing. The performance of this assay has not been established for use in a pediatric population, for neonatal screening, for testing of immunocompromised patients, for use by a point of care facility or for use with automated equipment.
The Focus Diagnostics Plexus™ HerpeSelect® HSV 1 and 2 IgG (with software) is a multiplexed immunoassay for qualitatively detecting and differentiating human IgG antibodies to HSV-2. Test principle is identical to the predicate device.
Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:
Device: Plexus™ HerpeSelect® HSV 1 and 2 IgG (with software)
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" in a quantitative manner for all performance aspects. However, the "Summary of Previous Studies for Plexus™ HerpeSelect® HSV 1 and 2 IgG (manual calculation)" table on page 2 provides clear performance metrics that can be interpreted as the device meeting expected performance for a similar predicate device.
For the purpose of this analysis, I will synthesize "acceptance criteria" from the described study results, assuming that the reported performance met the internal and regulatory expectations for market clearance.
| Acceptance Criteria (Inferred from Study Results) | Reported Device Performance (Plexus™ HerpeSelect® HSV 1 and 2 IgG) |
|---|---|
| Agreement with Plexus Software vs. Manual Calculation | |
| HSV-1 Index Agreement | 100% (95% CI: 0.977 - 1.00) for HSV-1 Positives (n=161) |
| 100% (95% CI: 0.398 - 1.00) for HSV-1 Equivocal (n=4) | |
| 100% (95% CI: 0.973 - 1.00) for HSV-1 Negatives (n=134) | |
| HSV-2 Index Agreement | 100% (95% CI: 0.974 - 1.00) for HSV-2 Positives (n=139) |
| 100% (95% CI: 0.590 - 1.00) for HSV-2 Equivocal (n=7) | |
| 100% (95% CI: 0.976 - 1.00) for HSV-2 Negatives (n=153) | |
| Performance in Indicated Populations | |
| Pregnant Women HSV-1 Specificity | 96.5% (95%CI 92.5-98.7%) |
| Pregnant Women HSV-1 Sensitivity | 92.2% (95%CI 86.1-96.2%) |
| Pregnant Women HSV-2 Specificity | 94.3% (95%CI 88.5-97.7%) |
| Pregnant Women HSV-2 Sensitivity | 95.5% (95%CI 91.2-98.0%) |
| Sexually Active Adults HSV-1 Specificity | 91.0% (95%CI 85.4-95.0%) |
| Sexually Active Adults HSV-1 Sensitivity | 96.5% (95%CI 92.0-98.9%) |
| Sexually Active Adults HSV-2 Specificity | 96.3% (95%CI 90.9-99.0%) |
| Sexually Active Adults HSV-2 Sensitivity | 97.4% (95%CI 93.9-99.1%) |
| Agreement with CDC HSV/CMV Panel | |
| Agreement with HSV-1 Positives | 100% (54/54), 95%CI 89.1-100% (for HSV-1 Positive only), 95%CI 84.6-100% (for Dual Positive) |
| Agreement with HSV-2 Positives | 100% (36/36), 95%CI 76.8-100% (for HSV-2 Positive only), 95%CI 84.6-100% (for Dual Positive) |
| Agreement with Negatives | 100% (32/32), 95%CI 89.1-100% (for Dual Negative) |
| Performance in Low Prevalence Population | |
| Low Prevalence HSV-1 Agreement with Negatives | 97.9% (46/47), 95%CI 88.7-99.9% |
| Low Prevalence HSV-2 Agreement with Negatives | 100% (71/71), 95%CI 94.9-100% |
| Cross-reactivity | |
| HSV-1 Cross-reactivity: CMV, EBV, VZV combined | 0-5% observed (e.g., 5.0% for CMV, 3.0% for VZV, 3.1% for EBV, for samples that were HSV-1 ELISA dual negative but positive for other viruses). Specifically, for dual negatives: One out of 37 samples was HSV-1 equivocal/positive, which was triple positive for CMV, VZV, EBV. |
| HSV-2 Cross-reactivity: CMV, EBV, VZV combined | 0-3% observed (e.g., 0.0% for CMV, 2.9% for VZV, 3.2% for EBV, for samples that were HSV-2 ELISA dual negative but positive for other viruses). Specifically, for dual negatives: One out of 37 samples was HSV-2 equivocal/positive, which was positive for VZV and EBV. |
| Reproducibility | |
| %CV of Positives (Inter/Intra-assay, Inter-Lab) | ≤10% for most positive samples, with some acceptable variations (e.g., Sample 9 HSV-1 Inter-assay %CV was 10.3%, Sample 3 HSV-1 Inter-assay %CV was 14.9%, HSV-2 Sample 3 Inter-assay %CV was 28.3%) |
| Inter-Lot %CV | Generally |
§ 866.3305 Herpes simplex virus serological assays.
(a)
Identification. Herpes simplex virus serological assays are devices that consist of antigens and antisera used in various serological tests to identify antibodies to herpes simplex virus in serum. Additionally, some of the assays consist of herpes simplex virus antisera conjugated with a fluorescent dye (immunofluorescent assays) used to identify herpes simplex virus directly from clinical specimens or tissue culture isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by herpes simplex viruses and provides epidemiological information on these diseases. Herpes simplex viral infections range from common and mild lesions of the skin and mucous membranes to a severe form of encephalitis (inflammation of the brain). Neonatal herpes virus infections range from a mild infection to a severe generalized disease with a fatal outcome.(b)
Classification. Class II (special controls). The device is classified as class II (special controls). The special control for the device is FDA's revised guidance document entitled “Class II Special Controls Guidance Document: Herpes Simplex Virus Types 1 and 2 Serological Assays.” For availability of the guidance revised document, see § 866.1(e).