Labs and Diagnostics

Question 1

What are the 4 laboratory tests?

Answer 1

pH testing

saline wet mount

KOH prep

PCR testing

Question 2

pH Testing

• what is normal pH of vagina?
• how is this tested?
• what disorders are associated with a pH greater than 4.5?

Answer 2

Normal pH is 3.8-4.5

Testing procedure:
-done with pH paper placed on the lateral wall of the vagina

Disorders:
-bacterial vaginosis, trichomoniasis, and atrophic vaginitis often cause pH greater than 4.5

Question 3

Wet Mount:

• indications
• interfering factors
• technique
• microscopic evaluation

Answer 3

Indications:
-vaginal itching, burning, rash, odor, discharge

Interfering factors:

• cant be done during menses
• avoid vaginal meds for 2-3d prior
• vaginal irritation from tampons or intercourse can alter results.

Technique:

• vaginal secretions obtained with a cotton swab via speculum
• sample of vaginal secretions placed on slide with a drop of saline and evaluated using microscopy.
• can put 1ml of saline in a test tube and place swab in test tube to agitate then transfer some to the slide (useful with copious discharge)

Micro eval:

• white cells
• clue cells
• lactobacilli
• trichomonads

Question 4

White cells:
-commonly seen on vaginal sample?

Clue cells:

• what are they?
• what do they indicate?

Lactobacilli:
-commonly seen on vaginal sample?

Trichomonads:
-how do these look different from WBC under microscope?

Answer 4

White:
normally seen on microscopy, but should be less than 10cells/high powered field.

Clue cells:
-what: vaginal epitherlial cells that are covered with bacteria, shaggy borders

-indicate: bacterial vaginosis

Lactobacilli:
-they are part of the normal flora, there will be less seen with conditions such as yeast and bacterial vaginosis

Trichomonads:

• have flagella, mobile, and zoom around the slide.
• slightly larger than WBC.

Question 5

KOH Prep

-technique

Answer 5

technique:
- few drops of 10% KOH solution added to vaginal secretions on a microscope slide.
- heating the slide with speed up the process of cellular destruction.
* KOH removes normal cells and bacteria clearing the field so that yeast buds and hyphae may be seen.

Question 6

Whiff Test with KOH

• technique
• what is a positive test indicate?

Answer 6

technique:
- when preparing the KOH slide you take a whiff to see if it has a fishy odor (amine)

positive test:
-bacterial vaginitis (93% specificity)

Question 7

PCR Testing:

• what is this test called?
• tests for what bacteria?
• if unable to get swab what other test can you use?
• procedure

Answer 7

NAAT = nucleic acid amplification testing

Tests for N. gonorrhoeae and C. trachomatis

Can use urine sample if unable to obtain vaginal fluid or endocervix.

Procedure:

• collect sample as directed by the test manufacturer.
• specimen collection should be delayed until greater than 1 hr after the pt has voided
• first-catch urine (collect first 10-30cc after initiating the stream)