What is the appropriate diagnostic and treatment approach for a patient presenting with vaginal discharge, considering the use of a KOH (Potassium Hydroxide) gram stain, urinalysis, and potential screening for STIs (Sexually Transmitted Infections)?

Diagnostic Approach to Vaginal Discharge

For vaginal discharge evaluation, order a wet prep with KOH preparation and vaginal pH testing as your immediate point-of-care diagnostic, combined with NAAT testing for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis to ensure comprehensive diagnosis. 1, 2

Immediate Point-of-Care Testing

Wet Prep Microscopy (First-Line Diagnostic)

• Collect vaginal swab from pooled vaginal secretions or lateral vaginal walls, avoiding cervical mucus contamination. 3, 2
• Examine within 30 minutes to 2 hours maximum—motile trichomonads lose viability rapidly after this window. 3, 1
• Place swab in tube with 1 mL normal saline or directly smear slide and add saline drop. 3

What to Look For on Saline Wet Mount

• Clue cells (epithelial cells covered with bacteria) indicate bacterial vaginosis. 3
• Motile flagellated trichomonads diagnose trichomoniasis, though sensitivity is only 40-70%. 3, 1
• Increased white blood cells suggest infection. 3
• Hyphae or budding yeast indicate candidiasis. 3

KOH Preparation (10%)

• Add KOH to separate slide to enhance visualization of pseudohyphae and budding yeast not visible on saline prep. 3, 1
• Perform "whiff test"—characteristic fishy odor when KOH mixed with vaginal secretions indicates bacterial vaginosis due to amines in discharge. 3

Vaginal pH Testing

• Dip pH paper in secretions on speculum tip after removal, read within 10 seconds. 3
• pH <4.5 suggests vulvovaginal candidiasis. 3, 1
• pH >4.5 indicates bacterial vaginosis or trichomoniasis. 3, 1

Laboratory NAAT Testing (Order Simultaneously)

Do not rely on wet prep alone—order NAAT panel for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis on every patient with vaginal discharge. 3, 2

Why NAAT is Essential

• Wet mount misses trichomoniasis 30-50% of the time, while NAAT has superior sensitivity. 3, 1
• Trichomonas prevalence equals or exceeds chlamydia and gonorrhea in certain populations, making simultaneous testing optimal. 3
• Specimens remain stable at room temperature for 7 days in laboratory-provided transport devices. 3, 4

Specimen Collection for NAAT

• Vaginal swabs, endocervical swabs, or urine can be used. 3, 4
• Place in laboratory-provided liquid Amies or transport medium. 4

Additional Testing Based on Clinical Scenario

For Bacterial Vaginosis Confirmation

• Quantitative Gram stain (Nugent criteria) is the most specific diagnostic standard, though wet prep with Amsel criteria is sufficient for routine clinical diagnosis. 3, 1
• Do not culture Gardnerella vaginalis alone—it lacks specificity for bacterial vaginosis diagnosis. 3, 1
• DNA hybridization probe or microbiome-based assays are more specific than G. vaginalis culture. 3

For Recurrent or Persistent Yeast Infections

• Culture is mandatory to identify non-albicans Candida species (occur in 10-15% of recurrent cases) that require different treatment. 3, 1, 4
• Submit swab in transport medium, stable at room temperature for 12 hours. 3

Urinalysis is NOT Indicated

Urinalysis has no role in diagnosing vaginal discharge—it evaluates urinary tract pathology, not vaginal infections. The question mentions urinalysis, but this is inappropriate for vaginal discharge evaluation. Focus diagnostic efforts on vaginal specimens as outlined above.

Critical Pitfalls to Avoid

• Never rely solely on wet mount for trichomoniasis—sensitivity is only 40-80% and requires examination within 30 minutes to 2 hours. 3, 1, 4
• Do not delay wet prep examination beyond 2 hours—organisms lose motility and become undetectable. 3, 1, 4
• Do not assume normal pH excludes all infections—use pH as adjunct, not sole diagnostic criterion. 1, 4
• Wide variation exists in microscopic interpretation between providers—proficiency is essential, and mixed infections may present atypically. 3, 1
• Do not forget STI testing—many infections coexist with vaginitis, requiring concurrent NAAT testing. 1

Physical Examination Findings

During speculum examination, note:

• Cervical friability and hyperemia indicate possible STI. 3
• White plaques on cervix that cannot be removed suggest condyloma acuminata. 3
• Red punctate lesions ("strawberry cervix") may indicate trichomoniasis. 3
• Prominent ectropion can cause significant vaginal discharge as normal developmental finding in adolescents. 3