VS-SENSE™ – Rapid Test for Evaluation of Vaginitis

The VS-SENSE™ TEST is a qualitative, visually-read swab for clinicians who wish to evaluate women with vaginal symptoms to rule out or rule in Bacterial Vaginosis and Trichomoniasis. The test indicates by color change whether a vaginal secretion has disordered acidity parameters. Results are based on combined indication of pH level and buffer capacity (watery secretion) which characterizes Bacterial Vaginosis and Trichomoniasis.

The VS-SENSE™ Test indicates abnormal vaginal discharge acidity by identifying changes in the pH level. The test cutoff is set at pH 4.7 (+0.3/-0.2 pH units; there may be variations due to sensitivity to buffer capacity). When the vaginal secretion has a pH above this cutoff, the test tip will be stained (or partially stained) green or blue. The test, when combined with clinical examination, assists the physician in diagnosing conditions which are associated with elevated pH levels.

VS-SENSE™ Advantages
  • High sensitivity and specificity
  • Helps diagnose a combined infection. When BV and Candida are mixed, and the pH in the vagina is above normal, the VS-SENSE™ test will give a positive result.
  • Rapid (10 seconds) office test
  • Clear to read and interpret.
  • Eliminates the need to send a discharge specimen for a lab test
  • VS-SENSE™ may improve accurate diagnosis medical outcomes by enabling appropriate treatment on the patient’s first visit
Performance Highlights
Sensitivity 91.8%
Specificity 92.9%
PPV 91.8%
NPV 92.9%
VS-SENSE™ the double parameter acidity test

One of the most used characteristics of BV and Trichomonas is the elevation of the pH level of the vaginal secretion. An average of 78% of the BV cases will be accompanied by a pH level of 4.7 or greater. Another characteristic is the dilution of the discharged secretion by extra-cellular fluid, which is detectable by measuring the percentage of protein per volume of discharge (Buffer Capacity).

Amsel’s criteria is one of the most common clinical diagnostic methods for BV. Three of four criteria must be met to establish an accurate diagnosis of BV in 90% of affected women.

  • Homogeneous, thin, watery vaginal discharge (color and amount may vary)
  • Amine (fishy) odor when potassium hydroxide solution is added to vaginal secretions (commonly called the “whiff test”)
  • Presence of clue cells (greater than 20%) on microscopy
  • Vaginal pH greater than 4.5

BV discharge is described as watery discharge due to the release of extracellular fluid across the vaginal cell walls. Regarding this biological behavior, the concentrations of the proteins and other large organic molecules are lower in BV secretions compared to normal secretions. Thus, the buffer capacity of the BV secretions is lower than that of normal secretions.

Buffer is a solution that can keep its relative acidity or alkalinity constant. Buffer Capacity of solution is the amount of acid or base it can handle before the pH of the solution changes.

The sensitivity of a regular pH test is about 77-78%. Therefore, a regular pH test will miss at least 22% of cases (22% false negative indications) in which BV is accompanied by normal pH.

VS-SENSE™ supports diagnosis of BV by detecting two disorder parameters in a vaginal secretion: pH level above normal and watery secretion – with low buffer capacity.

The VS-SENSE™ is a testing swab coated with unique chemical composition. The swab tip reacts as a pH indicator due to the incorporation of Nitrazine yellow in the polymer matrix. In addition, the VS-SENSE™ has hydrophobic characters in contrast to the hydrophilic character of commercial pH papers like Nitrazine paper®. This makes the VS-SENSE™ sensitive to buffer capacity of a solution as well as to pH. The lower the buffer capacity, the greater the sensitivity ofthe VS-SENSE™ to pH.The tip changes color in lower pH than comparable solutions that have a higher buffer capacity.

The color of the VS-SENSE™ swab tip will change from yellow to green or blue when the swab comes into contact with vaginal secretions whose pH and /or buffer capacity is abnormal. The color changes when the secretion pH is above 5.2 units. In addition, the color changes will occur in a dynamic range between pH levels of 4.3 to 5.2, depending on the levels of the secretion buffer capacity.

To summarize, unlike other standard commercial pH tests like Nitrazine paper, the VS-SENSE™ indicator can combine two Amsel criteria in a dynamic range, high pH levels (4.3 and above) and watery discharge. When BV and Candida are mixed, the pH in the vagina will be above normal, and the VS-SENSE™ test will give a positive result.

Vaginitis - Vulvovaginitis
  • Vaginitis is a very common feminine disease affecting millions each year.
  • Vaginitis accounts for over 50 percent of all gynecologic office visits.
  • The key to proper Vaginitis treatment is accurate diagnosis.
  • There is a need for a tool that enables a clinician to diagnose the causes of the patient’s Vaginitis and prescribe the correct treatment.

Vaginitis – Vulvovaginitis, is an inflammation or infection of the vagina. It can also affect the vulva, which is the external part of a woman’s genitals. It is symptomatically observed by a watery discharge with burning and itching of the vulva.
Vaginitis is common, especially in women in their reproductive years. It is one of the most common reasons for gynecological consultation. It usually happens when there is a change in the balance of bacteria or yeast that are normally found in the vagina. There are different types of vaginitis, and they have different causes, symptoms, and treatments.

Normal levels of vaginal pH fluctuate between 3.8 and 4.5, which is slightly acidic. A normal, healthy vagina contains both Lactobacillus sp. (“good bacteria”) and harmful bacteria. Normally, the Lactobacillus flora are predominant and produce lactic acid (and H2O2) to keep the vaginal pH level between 3.8 and 4.5.

Various factors may cause a loss of lactobacillus bacteria in the vagina, including use of: antibiotics, vaginal medications, systemic hormones, contraceptive preparations, and douches; as well as sexual intercourse and STDs. Some of these situations may cause the harmful bacteria to overgrow. When this occurs the harmful bacteria “over control”, which can lead to bacterial vaginosis (BV) may occur. With BV and parasitic infections the vaginal pH usually increases to 5.0 or 6.0 and above, which are above the normal range.

The three common types of vaginitis

  • Bacterial Vaginosis (BV)
  • Trichomonas Vaginalis (Trichomoniasis)
  • Yeast (Candida Infection)

Bacterial Vaginosis (BV)
BV is the most common cause of abnormal vaginal discharge in women of childbearing age, but may also be encountered in menopausal women, and is rather rare in children. The prevalence in the United States is estimated to be 21.2 million (29.2%) among women ages 14–49, based on a nationally representative sample of women who participated in NHANES 2001–2004.

BV is caused by high concentration of gram-negative rods of anaerobic bacteria like:Gardenerella vaginalis, Mycoplasmas hominis Ureaplasma, Prevutella spp., Mobiluncus spp., Peptostreptococcus spp. This flora replacesthe normal flora: Lactic acid and H2O2 to produce Lactobacillus sp. BV doesn’t usually cause any vaginal soreness or itching, but often causes unusual vaginal discharge.
BV is not serious for the vast majority of women, although it may be a concern if symptoms of BV develop in pregnancy and there is a history of pregnancy-related complications. Around half of women with BV have no symptoms.

Trichomonas Vaginalis (TV)
TV is a globally occurring anaerobic Uorgenital Protozoa, which colonizes the epithelium of the human urogenital tract. Although often asymptomatic, TV infections can cause inflammation in the cervix, the vagina, and the urethra. Based on estimates of the World Health Organization (WHO)from 2008, trichomoniasis constitutes the most prevalent non-viral sexually transmitted disease (STD) worldwide, affecting more than3.7 million people every year.

Yeast infection – Candidiasis
Candidiasis is an infection caused by a yeast called Candida.Vulvovaginal candidiasis (VVC) is an infection caused by a Candida species that affects millions of women every year. Although candida albicans is the main cause of VVC; the identification of non-candida albicans candida (NCAC) species, especially candida glabrata, as the cause of this infection appears to be increasing. Candida normally lives inside the body (in places such as the mouth, throat, gut, and vagina) and on skin without causing any problems. Sometimes Candida can multiply and cause an infection if the environment inside the vagina changes in a way that encourages its growth. Candidiasis in the vagina is commonly called a “vaginal yeast infection.” Other names for this infection are “vaginal candidiasis,” “vulvovaginal candidiasis,” or “candidal vaginitis.”
Although most vaginal candidiasis is mild, some women can develop severe infections involving redness, swelling, and cracks in the wall of the vagina.

Approximately 75% of all women will experience at least one episode of VVC during their lifetime.

Symptoms of vaginitis
The symptoms of vaginitis differ according to the type of infection


Table 1: Symptoms of vaginitis by type of infection
Type of Infection Symptoms and Signs
Bacterial Vaginosis (BV) Discharge become white or grey
Thin homogeneous vaginal discharge – watery discharge.
Positive amine test – strong fishy odor.
Increased vaginal pH to level of above 4.5.
Trichomoniasis More extensive inflammation.
Erosion of the epithelial lining that is associated with itching, burning and pain during urination.
Smelly or foamy discharge.
Yellow or gray-green discharge.
Increased vaginal pH to levels above 4.5.
Yeast Vulvovaginal itching irritation or soreness.
Whitish, cheesy discharge.
Pain during sexual intercourse
Pain or discomfort when urinating
Abnormal vaginal discharge
The pH level of the vaginal discharge remains normal.

Mixed Vaginal Infection
This is a combination which is rarely detected and occurs in over 20% of cases that are difficult to detect. This is because the Candida symptoms cause doctors to assume that it is Candida and not mixed vaginal infection.
Usually, symptoms lead to offering Candida treatment which is only a partial treatment.
Abnormal discharge persists due to partial treatment, requiring a second and third visit to the clinic .In cases where a patient has an infection of both BV and Candida, both of these inflammations should be treated. Trichomoniasis and BV are relatively common mixed infections, both benefiting from elevated vaginal pH and anaerobic environment.

What are the complications of BV?

In most cases, BV causes no complications, but evidence has accumulated that associates BV with serious medical complications including:

  1. Increased chance that an HIV-infected woman can pass HIV to her sex partner.
  2. Increase in the development of Pelvic Inflammatory Disease (PID) following surgical procedures such as a hysterectomy, abortion, or post–caesarean delivery endometritis.
  3. If it occurs during a pregnancy, increased risk of miscarriage, low birth weight infants, preterm delivery, premature rupture of the fetal membranes, chorioamnionitis, postpartum complications in the infant, and endometritis following vaginal delivery.
  4. Higher risk of acquiring sexually transmitted diseases (STDs) and HIV infection and of transmitting HIV infection.


Because of these associated complications, accurate diagnosis of BV is increasingly important in pregnancy and prior to pelvic surgery

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