How do you treat white blood cells (WBC) in a wet prep?

Treatment of White Blood Cells on Vaginal Wet Prep

You do not treat white blood cells (WBCs) on wet prep directly—you treat the underlying infection causing the inflammatory response. The presence of WBCs is a diagnostic clue, not a diagnosis itself, and requires identification of the specific pathogen to guide appropriate antimicrobial therapy.

Clinical Approach to WBCs on Wet Prep

Step 1: Determine if WBCs Indicate Infection

• The presence of WBCs on saline microscopy is an additional criterion supporting pelvic inflammatory disease (PID) diagnosis when combined with uterine/adnexal tenderness or cervical motion tenderness 1, 2
• If cervical discharge appears normal and no WBCs are found on wet prep, PID is unlikely and alternative causes of symptoms should be investigated 1
• Moderate to many WBCs correlate with sexually transmitted infections (STIs), specifically increasing the odds of gonorrhea, chlamydia, or trichomoniasis (OR 1.58 for moderate, OR 2.47 for many WBCs) 3

Step 2: Identify the Specific Pathogen

The treatment depends entirely on what organism is causing the WBC elevation. Look for these specific findings on wet prep:

Trichomoniasis

• Moving flagellated trichomonads on wet mount indicate Trichomonas vaginalis 2
• Treatment: Metronidazole 2 g orally as a single dose 1
• Note that wet mount microscopy misses trichomoniasis in 30-50% of cases; more sensitive testing (culture, nucleic acid probe, or PCR) may be needed 2

Bacterial Vaginosis

• Clue cells (bacteria-covered epithelial cells) on wet prep suggest bacterial vaginosis 2
• Requires positive whiff test and pH >4.5 for diagnosis 4
• Treatment: Metronidazole 500 mg orally twice daily for 7 days (only if symptomatic) 5

Candidiasis

• Hyphae or budding yeast on wet prep indicate candidal infection 1
• Associated with normal vaginal pH (<4.5) 1
• Treatment: Topical azole agents (fluconazole 150 mg single dose orally, or intravaginal azole preparations for 1-7 days depending on formulation) 1

Gonorrhea/Chlamydia

• WBCs without visible organisms should prompt testing for N. gonorrhoeae and C. trachomatis 1, 2
• Nucleic acid amplification tests (NAATs) are the most sensitive and specific 6
• Treatment for chlamydia: Azithromycin 1 g orally as single dose OR doxycycline 100 mg orally twice daily for 7 days 5
• Gonorrhea requires ceftriaxone-based regimens per current CDC guidelines 6

Step 3: Consider Pelvic Inflammatory Disease

If WBCs are present with any of the following, initiate empiric PID treatment immediately:

• Uterine/adnexal tenderness or cervical motion tenderness 1, 2
• Oral temperature >101°F (>38.3°C) 1, 2
• Abnormal cervical or vaginal mucopurulent discharge 1, 2
• Elevated ESR or CRP 1, 2

PID treatment requires broad-spectrum coverage of N. gonorrhoeae, C. trachomatis, anaerobes, gram-negative facultative bacteria, and streptococci 1

Critical Management Considerations

• Coinfection is common: 35-38% of pregnant women with trichomoniasis have another STI or urinary tract infection 4, and trichomoniasis coexists with bacterial vaginosis in 15% of cases 4
• Test for all pathogens present and treat accordingly 1
• Vaginal WBC counts ≥11 WBCs/HPF have limited diagnostic utility in isolation (sensitivity 48-53%, specificity 67-69% for STIs) 7
• Incorporate additional factors: age, urine leukocyte esterase results, and clinical presentation improve diagnostic accuracy beyond WBC counts alone 7
• Patients should abstain from sexual intercourse for 7 days after completing therapy 5
• Sex partners must be evaluated and treated if they had sexual contact within 60 days of diagnosis 5

Common Pitfalls to Avoid

• Do not treat WBCs empirically without identifying the pathogen—this wastes antibiotics and promotes resistance 5
• Do not assume all WBCs indicate infection—normal pregnancy elevates WBC counts by 36% (neutrophils by 55%) 8
• Do not rely solely on wet prep for trichomoniasis diagnosis given the 30-50% false-negative rate 2
• Do not miss PID by requiring all diagnostic criteria—maintain a low threshold for empiric treatment given the risk of reproductive complications 1