(122 days)
The VS-SENSE™ TEST is a qualitative, visually-read swab for clinicians who wish to evaluate women with vaginal symptoms. The device is a vaginal pH indicator swab intended to be used in conjunction with other clinical examinations, such as the Amsel criteria or the Nugent Gram stain, to aid in determining conditions characterized by elevated vaginal pH, such as bacterial vaginosis.
The VS-SENSE™ comprises a regular vaginal swab with its tip coated by an indicating polymer. When the indicating tip has been in contact with vaginal secretion, with elevated pH level, the user will observe a blue or green stain on the yellow background of the tip. The stains on the tip are caused by the sensitivity of a proprietary polymer, which coats the tip and contains the traditional indicator - Nitrazine Yellow. The VS-SENSE™ polymer matrix has a specific composition of ingredients that changes color when the pH of the vaginal discharge is greater than 4.7 +0.3/-0.2.
Acceptance Criteria and Study for VS-SENSE™
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria for the VS-SENSE™ device are implicitly based on demonstrating substantial equivalence to the predicate device, PHEM-CHEK™. The key performance metrics compared are sensitivity and specificity, both as a standalone test and as a second test within the Amsel Criteria procedure.
| Characteristic | Acceptance Criteria (from Predicate PHEM-CHEK™) | Reported VS-SENSETM Performance |
|---|---|---|
| Sensitivity (Stand-alone) | 91% | 86.3% |
| Sensitivity (As 2nd test of the Amsel Criteria procedure) | 99% | 97% |
| Specificity (Stand-alone) | 84.2% | 93.9% |
| Specificity (As 2nd test of the Amsel Criteria procedure) | 43.42% | 43.5% |
Note: The document states that the VS-SENSETM's performance is "Based on pivotal study results," implying that these reported values represent the device's actual performance in the study and were considered acceptable for substantial equivalence.
2. Sample Size and Data Provenance for the Test Set
The document does not explicitly state the sample size used for the test set or the data provenance (e.g., country of origin, retrospective/prospective nature). It only refers to "pivotal study results" when reporting the sensitivity and specificity values.
3. Number of Experts and Qualifications for Ground Truth
The document does not specify the number of experts used to establish the ground truth for the test set or their qualifications. However, it mentions that the device is intended to be used in conjunction with "other clinical examinations, such as the Amsel criteria or the Nugent Gram stain," which are often interpreted by trained medical professionals.
4. Adjudication Method for the Test Set
The document does not provide information on the adjudication method used for the test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
The document does not mention a multi-reader multi-case (MRMC) comparative effectiveness study. The comparison presented is between the standalone performance of the VS-SENSE™ and the predicate device, and their performance as a second test within the Amsel Criteria procedure. There is no information about how much human readers improve with AI vs. without AI assistance, as this device uses a visual indicator and not AI.
6. Standalone Performance Study
Yes, a standalone study was done. The document reports "Stand-alone" sensitivity and specificity for the VS-SENSE™ as 86.3% and 93.9% respectively, and for the predicate PHEM-CHEK™ as 91% and 84.2% respectively. This indicates that the algorithm's performance without human-in-the-loop assistance was evaluated. The device itself is a visually-read swab, so "algorithm" here refers to the chemical reaction and visual indication, interpreted by a user.
7. Type of Ground Truth Used
The type of ground truth used is implied to be based on an assessment of conditions characterized by elevated vaginal pH, such as bacterial vaginosis, likely diagnosed using established clinical methods like the Amsel criteria or Nugent Gram stain. These methods typically rely on expert interpretation of clinical signs and microscopic findings.
8. Sample Size for the Training Set
The document does not provide information about the sample size for the training set.
9. How Ground Truth for the Training Set Was Established
The document does not provide information on how the ground truth for the training set was established.
§ 862.1550 Urinary pH (nonquantitative) test system.
(a)
Identification. A urinary pH (nonquantitative) test system is a device intended to estimate the pH of urine. Estimations of pH are used to evaluate the acidity or alkalinity of urine as it relates to numerous renal and metabolic disorders and in the monitoring of patients with certain diets.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 862.9.