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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.

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.

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The AmniScreen Home Detection Liner Kit is intended to detect possible leakage of amniotic fluid when vaginal wetness is experienced during pregnancy by indicating pH level. pH levels greater than or equal to 5.2 produce a blue-green color. Patients are instructed to report or show test results to their healthcare provider for interpretation and medical care.

The AmniScreen™ Home Detection Liner Kit contains a Testing Panty-Liner (TPL) and a Drying Tray (DT). The TPL comprises a regular panty-liner and an indicator strip assembled into the panty-liner, covered with two layers of one-way perforated film. The indicator strip is removed after use and placed in the DT for 30 minutes before reading the test results. When the indicator strip has been in contact with amniotic fluid, the user will observe a blue-green stain on the yellow background of the strip. An elevated pH level of the fluid causes the stain. The stains on the strip are caused by the sensitivity of a proprietary polymer, which coats the strip and contains the traditional indicator - Nitrazine Yellow, to pH levels above 5.2 units. The proprietary polymer is also sensitive to certain concentrations of ammonium in the tested fluid, and when the color changes are created by fluids with a certain concentration level of ammonium, and pH levels up to 7.0 units, these color changes are reversible and during a drying period of 30 minutes the blue-green stains fade back to yellow.

Acceptance Criteria and Study Details for AmniScreen™ Home Detection Liner Kit

This information is extracted from the provided 510(k) summary for the AmniScreen™ Home Detection Liner Kit.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied by the claim of "substantial equivalence" to the predicate device, specifically regarding sensitivity and specificity. The provided summary only gives the reported performance of the AmniScreen device, with the predicate device's performance serving as the unstated benchmark.

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size for Test Set: 339 pregnant participants.
• Data Provenance: The study involved participants arriving at hospitals at three different test sites, suggesting a prospective, multi-site clinical study. The country of origin is not explicitly stated, but the submitter is based in Israel and the FDA review document is from the USA, so the study could have been conducted in either or both.

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

The document mentions that the performance of AmniScreen™ was demonstrated by "a Nitrazine Paper test performed by clinicians."

• Number of Experts: Not explicitly stated, but implies multiple clinicians (as it refers to "clinicians" generically).
• Qualifications of Experts: "Clinicians." No specific qualifications (e.g., years of experience, specialty like OB/GYN) are provided beyond being a clinician who could perform a Nitrazine Paper test.

4. Adjudication Method for the Test Set

The adjudication method is not explicitly stated. However, given that the performance was "demonstrated by a Nitrazine Paper test performed by clinicians," it suggests that the Nitrazine Paper test results served as the reference standard or "ground truth" against which the AmniScreen™ results were compared. There is no mention of a consensus process among clinicians for determining the ground truth for each case.

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

No, an MRMC comparative effectiveness study was not explicitly described in the provided summary. The study focused on the standalone performance of the AmniScreen™ device compared to a clinician-performed predicate (Nitrazine Paper test). There's no mention of human readers improving with or without AI assistance, as this is a diagnostic device, not an AI-assisted diagnostic tool.

6. If a Standalone Study (Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, a standalone study was done. The "sensitivity and specificity of the AmniScreen™ Home Detection Liner Kit in the study" report the performance of the device itself (though it relies on a patient or trained staff to read the result, the performance metrics are for the device's ability to detect the condition). The study also examined the correlation between user readings and trained staff readings to assess its suitability for home use, which indirectly speaks to its standalone interpretation for the intended user.

7. The Type of Ground Truth Used

The ground truth used was predicate device performance / clinical assessment. Specifically, the summary states: "The sensitivity and specificity of the AmniScreen™ Home Detection Liner Kit in the study were substantially equivalent to predicate device performance, which was demonstrated by a Nitrazine Paper test performed by clinicians."

8. The Sample Size for the Training Set

The document does not provide information regarding a separate training set or its sample size. The summary describes a "pivotal clinical study" with 339 participants, which appears to be the primary study for performance evaluation (test set). For the device's development (training), the summary only mentions "Lab tests to prove efficacy and pH cutoff were performed in the developer's labs," but no specific training data set or size is provided.

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

As no specific training set is detailed, the method for establishing its ground truth is not provided. The development process mentions "Lab tests to prove efficacy and pH cutoff," implying a controlled laboratory environment where pH levels were likely experimentally varied and verified to establish the device's response characteristics during its design and development phase.

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