Vaginosis and Vaginitis (Yeast Infection) Lab Testing: What You Should Know

 Vaginosis (yeast infection) is a bacterial infection/inflammation commonly caused by the overgrowth of bacteria in the vagina. Vaginitis can also be defined as the inflammation of the vagina caused by several factors, including an irritant, allergy, and a decrease in estrogen levels. Vaginitis is very popular with women in the childbearing age. This bacterial infection affects around 21 million women in the world, most of whom are aged between 14 and 49 years. This is according to data released by the CDC (Centers for Disease Control and Prevention). This condition is characterized by abnormal vaginal discharge, pain, burning sensation, and itching in and around the genitals. The vulva (external genitals) also be affected by this, causing it to be inflamed, thus leading to another condition known as vulvovaginitis. Cervicitis or inflammation of the cervix may also occur from this as well.  

The vagina is home to a host of good bacteria ‘microbes’ that help discourage the growth of disease-causing bacteria by maintaining a moderately acidic environment. These bacteria keep a healthy acidic balance hence keep the vagina protected.  The bacteria involved include lactobacilli, corynebacterial, some yeast, and a mixture of other microbes.  

It is normal for one to produce a small amount of vaginal discharge every day. The discharge is usually milky or clear and with varying quantities and consistency, all of which depend on the woman’s menstrual cycle.  

Causes of Yeast Infection (Vaginitis and Vaginosis)  

Yeast infection may occur if/when the healthy balance of flora is disrupted.  Any form of irritation on the vulva and vaginal tissues may lead to vaginitis as well.   

The most common causes of vaginosis/vaginitis are infections due to: 

  • Bacterial vaginosis: This type of infection is caused by changes in the vaginal flora. It is commonly characterized by an increase in other bacteria (mycoplasma hominis and Gardnerella vaginalis, among others), and a decrease in the number of lactobacilli populations.   
  • Yeast (Candida albicans) infection: Commonly known as candidiasis and caused by candida species  
  • Trichomonas vaginalis infection: Also known as trichomoniasis or ‘Trich,’ a sexually transmitted disease (parasitic).   

Other Causes 

  • Allergic reaction to irritants from feminine hygiene products, petroleum products used within the vagina, tight underclothing, bubble baths, deodorant soaps, perfumes, latex condoms, and use of fabric softeners in sheets.   
  • Loss of lubrication and thinning of vaginal skin due to low estrogen levels. Decreased estrogen levels cause a condition known as atrophic vaginitis, which only affects women in their menopause.  
  • Foreign object/body in the vagina. This can be a forgotten tampon (in a menstruating woman) or a small piece of toilet paper in a child.  

Bacterial vaginosis tends to increase the risk of infections in the woman’s genitalia. The most common of these are sexually transmitted diseases. 

Some of the STDs that can cause vaginitis or vaginosis include:  

  • Gonorrhea 
  • Herpes 
  • Chlamydia 
  • Human Papilloma Virus (HPV) 
  • HIV 

It is worth noting that vaginosis/vaginitis can occur in both girls and women of childbearing age. These conditions are, however, more common in sexually active individuals as compared to non-active ones. This, however, doesn’t mean girls who are not sexually active cannot contract the infection. Studies also show that vaginosis/vaginitis can be a result of more than one cause.  

Risk Factors for Vaginosis/Vaginitis 

These include: 

  • Pregnancy (hormonal changes during pregnancy may cause vaginal irritation)  
  • Antibiotic use (this reduces populations of good bacteria in the vagina)  
  • Frequent douching (causes loss of healthy flora)  
  • Sexual activity (with a new partner and/or multiple sex partners)  
  • IUD (intrauterine device) use  
  • Oral contraceptive use  
  • Poor hygiene  
  • Smoking 
  • Emotional/physical stress 
  • Underlying health conditions (e.g., poorly controlled diabetes, dermatitis, etc.)  

Sign and Symptoms of Vaginosis/Vaginitis 

There are no specific symptoms and signs associated with vaginosis. Some of the perceivable ones include burning, itching, redness, pain, and swelling of the vagina. The more distinctive signs are depending on the main cause of the same. These may include:  

  • Bacterial infection (vaginosis): This is characterized by a smelly thin, milky, or grey vaginal discharge, commonly surfacing after sexual intercourse. The unpleasant ‘fishy’ smell is mainly due to the increased pH levels and the presence of amines (chemicals) in the vagina. Most women with bacterial vaginosis (85%) hardly have any symptoms. 
  • Yeast infection (candidiasis):  Candidiasis is characterized by a white and thick vaginal distance that resembles cottage cheese.  The person may also experience itching, redness, and swelling, burning with urine, and painful sexual intercourse.  
  • Trichomoniasis: This causes a yellowish-greenish, unpleasant smelling, and sometimes ‘frothy’ vaginal discharge, as well as redness, itching, painful urination, and painful sexual intercourse. There may also be visible small red sores on the vaginal walls and cervix (during a pelvic exam). Most women with trichomoniasis do not have noticeable symptoms.  
  • Atrophic vaginitis: This condition affects women approaching or in menopause. It is characterized by thinning of vaginal walls. The women may experience itching, burning, vaginal dryness, and painful sexual intercourse. Some bleeding may occur after having sex.  

These infections rarely lead to pelvic inflammatory disease (PID) or inflammation of the cervix.  Vaginosis can (in some cases) cause preterm birth, low birth weight in infants, premature labor, and even be transmitted to the newborn.  Vitamin D deficiency in pregnant women is also believed to increase the risk of bacterial vaginosis too. Bacterial vaginosis is commonly associated with miscarriages, and especially in the second trimester of the pregnancy.  

Tests for Vaginitis/Vaginosis 

The process of diagnosis vaginosis and vaginitis is dependent on the risk factors for infection, and the patient’s age. For women within the childbearing age bracket, tests may include a physical exam, one’s medical history, and a pelvic exam. The doctor will also want to know what symptoms you have, how long they have lasted, the frequency of the same, any prescribed medications you might have taken (including oral contraceptives and antibiotics), as well as over-the-counter treatments used.  You might also be required to share information about your sexual history and personal habits (use of scented soaps, tight clothing, and douching, etc.) as well.  The health practitioner will use the information provided to determine the best type of tests to be done.  

The main reason for ordering the tests is to diagnose vaginosis or vaginitis, as well as determine the primary cause of the condition. This helps guide the practitioner on a plausible medication or treatment method.  These tests also help identify treatment options your body will respond to, and especially if you have had recurrent infections.  

Diagnosis of bacterial vaginosis (clinically) is recommended if 3 of 4 of the following symptoms are present. 

  • 4.5 or higher vaginal pH  
  • Graying-white vaginal discharge 
  • Fishy odor when 10% potassium hydroxide is added 
  • Presence of ‘clue’ cells (described below)   

Lab Tests  

The health practitioner may collect a few samples to be sent to the laboratory or perform a few tests in the clinic or medical office as well.  Bacterial vaginosis is, however tested through direct examination of vaginal secretions. The samples can then be examined microscopically as a Gram-stained or wet mount slide.  

1. Wet Prep (Wet Smear/Mount)  

The vaginal discharge sample is placed on a glass slide, which is then examined through the microscope.  The findings include: 

  • Candida: Yeast may be seen in the form of branch-like structures, also known as pseudohyphae, or budding yeast.  
  • Bacterial vaginosis: This is basically the presence of cells (from the vaginal lining) coated by bacteria. These are also known as ‘clue’ cells. The vaginal discharge will also have very few to no white blood cells.  
  • Trichomonas: These are oval-shaped parasites with moving flagella (hair-like structures). An abnormally high number of white blood cells may also be seen in the sample. 

2. Gram Stain 

The vaginal discharge sample is placed on a glass slide, which is then stained with the gram stain (a special dye). The stain is put under the lens where health practitioner looks out for specific cell types, type of bacteria, and the quantity. Should 20% or more of these cells be covered in the ‘clue cells’ (bacteria), then the patient may have bacterial vaginitis. A reduction in Lactobacillus bacteria may also be an indicator of bacterial vaginosis. The Gram stain may also help detect the presence of yeast cells too. This testing method might, however, not detect the trichomonas parasite.  

3. pH Test  

This involves testing vaginal discharge’s acidity. pH levels of less than 4.5 are perfectly normal, though they could also indicate a yeast infection. Any pH greater than 5.0 is seen with trichomoniasis and bacterial vaginosis infections.  

4. KOH Prep  

The sample of the discharge collected is placed on a glass slide, where a drop of potassium hydroxide (at 10% concentration) is added. The findings include:  

  • Bacterial vaginosis: A fishy odor is released, showing the presence of amines in the discharge. 
  • Candidiasis: KOH makes it possible to see the pseudohyphae and yeast in the sample. 
  • Trichomoniasis: An unpleasant odor is released. 

Additional tests may be required to identify the causes of vaginosis/vaginitis. These include: 

  • Molecular methods: To identify yeast infection, bacterial vaginosis, and trichomonas. Examples of molecular methods include NAAT and nucleic acid amplification.  
  • Rapid point-of-care tests:  Used to detect bacterial vaginosis and trichomonas.  

5. Vaginal Cultures  

This method of testing isn’t recommended for bacterial vaginitis diagnosis. The growth of bacterial in the culture can be quite difficult to understand. This is because Gardnerella vaginalis can be cultured from asymptomatic and healthy women.  

  • Candidiasis: A fungal culture may be used to help diagnose recurrent and persistent infections. It can also be used to determine the type of yeast present.  
  • Trichomoniasis: A special culture for the same may be used to detect trichomonads. This test is recommended if the microscopic exam seems insufficient.  

6. Other Tests 

Other tests may be ordered if the health practitioner suspects the patient has contracted STDs. Some of the STDs tested for include: 

Follow-up tests may also be required to determine the reason for some cases, especially recurrent yeast infections. An underlying condition, such as diabetes, may be the reason for the recurring conditions.