• VS-Sense Test is comprised of vaginal swab with a polyester tip.
  • The tip is impregnated with pH sensitive polymer matrix containing Nitrazine indicator.
  • The swab tip changes color when it comes in contact with vaginal secretions presenting elevated pH (abnormal acidity) or low buffer capacity (watery discharge).
  • A change of color from pale yellow to green or blue (even if only part of the tip change color) is easy to identify, considered a positive reading.
  • No color scale is needed to interpret the results.
  • Buffer solution is a solution that can keep its relative acidity or alkalinity constant.
  • Buffer Capacity: The capacity of a buffer is the amount of acid or base it can handle before the pH of the solution changes.

Bacterial vaginosis & Trichomoniasis secretions looks watery. Decrease concentration of protein and other large molecules by increase of extracellular fluid, causing lower buffer capacity values of the samples.

  • pH – 78% of the Bacterial Vaginosis cases will be accompanied by a pH level above 4.5 (regular pH indicators like pH paper will miss at least 22% of cases in which BV is accompanied with normal pH).
  • Buffer Capacity – In “watery” discharge (like in cases of BV and Trichomonas) the protein and salt concentration in the vaginal discharge is lower, hence, the buffer capacity is lower.

The BV Test Threshold is set as follows:

  • pH ≤ 4.2 the swab tip stays yellow.
  • pH ≥ 5.2 the swab tip stains blue-green.
  • 5.2 > pH > 4.2 the swab tip stains blue-green only if the buffer capacity is low.

Performance Highlights

Sensitivity: 86.3% - 91.8%
Specificity: 93% - 93.4%
PPV: 91.8% - 92%
NPV: 89% - 93%
Accuracy: 90% - 92%

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