Infectious Vulvovaginal Disease:Obstacles to Performing Wet Mount Exams

December 31, 2006

Accurate diagnosis of nonviralinfectious diseases ofthe vagina is largely contingenton the clinician’s abilityto do a sophisticated wetmount/potassium hydroxide (KOH)preparation examination-more specificallywhat is termed a “level II wetmount examination” (Table). Clinicalassessment in conjunction with a properwet mount/KOH analysis will usuallyidentify the causative organism orsuggest exclusion of diagnostic possibilities(Figure).

Accurate diagnosis of nonviralinfectious diseases ofthe vagina is largely contingenton the clinician's abilityto do a sophisticated wetmount/potassium hydroxide (KOH)preparation examination--more specificallywhat is termed a "level II wetmount examination" (Table). Clinicalassessment in conjunction with a properwet mount/KOH analysis will usuallyidentify the causative organism orsuggest exclusion of diagnostic possibilities(Figure).

 Table - Contents of level II wet mount preparation analysis
Point of analysis Finding

Squamous cells Quantity; character (presence or absence of basilar cells)

Bacterial adherence Degree (0 to 4+); presence or absence of valid “clue cells”

White blood cells Quantity; presence or absence of clumping

Bacteria Lactobacilli (0 to 4+); presence or absence of Mobiluncus; quantity (0 to 4+); description of major bacteria present

Trichomonads Presence or absence

Fungi Presence of budding yeast; presence of pseudomycelia or mycelia

pH < 4.5 or > 4.5

Volatile amine (whiff) test Positive or negative

From Monif GRG.

With a relatively limited numberof causative agents to deal with, properdiagnosis would be anticipated in ahigh percentage of cases. Unfortunately,expectations and reality do notalways coincide. The question thenbecomes why not?

To do even a level I wet mount/KOH analysis (identification of "cluecells" and microbes, specifically protozoaand yeast) is time-consuming andrequires specialized equipment andsupplies and proper disposal of specimens.In many instances, the physicianmust leave the examination room.

Current Procedural Terminology(CPT) codes for wet mount/KOHreimbursement have been inadequate,since the procedure has beenviewed as an adjunct to the pelvic examinationand its true cost has beenunderwritten by payment for thepelvic examination. Unfortunately,this conceptualization failed to takeinto account that the wet mount/KOH examination required for awoman with vulvovaginal symptomatologyand one done as a part of annualhealth care maintenance havemarkedly different requisites. In additionto level I points of analysis, thelevel II examination includes determinationof the following:

  • Number of white blood cells perrepresentative high-power field.
  • pH.
  • Gross morphologic identificationof types of bacteria present and theirrelative density.
  • Inducibility of certain odors by theaddition of KOH.
  • Number and types of squamousepithelial cells.

These findings must all beascertained to fulfill the first requisiteof the scientific method: obtainingthe most information possible as aprerequisite to forming a hypothesis/diagnosis.

The regulations established bythe Clinical Laboratory ImprovementAct were intended to enhance the qualityof observations derived from wetmount/KOH examinations; however,they have had just the opposite effect.Many office laboratories no longer performwet mount/KOH examinations.The AMA has steadfastly refused toacknowledge a need for separate CPTcodes for level I and level II wetmount/KOH examinations.

An equally important problemhas been the lack or relative lack ofinstruction and monitoring of interpretativeresults derived from wetmount/KOH analysis in residencyprograms for family physicians, emergencymedicine physicians, and obstetricians/gynecologists. In the early1980s, Herman Gardner wrote, "Howsad it is when our star chief residentpasses the American Board examinationswithout a falter and displays asuperior knowledge of dozens of raritiesin the specialty but . . . falterswhen attempting to instruct others inhow to prepare a saline wet mount ofvaginal secretions."1 Since then, littleto no improvement has occurred. Exacerbatingthis deficit in training isthe downgrading of instruction in theuse of the microscope within medicalschool curriculums.

The consequence of these variousfactors is that too often diagnosesare predicated on clinical grounds,Gram stain analysis, or level I examinations.All that itches is not yeast,and all that smells fishy is not justbacterial excess syndrome (BES) orbacterial vaginosis (BV).

Recently, authors have alluded tothe consequences of suboptimal training.Ledger and colleagues2 evaluatedthe ability of residents in obstetricsand gynecology to make the diagnosisof Candida vaginitis using wetmount/KOH preparations. A positivemicroscopic examination correlatedwith a positive culture 32.6% of thetime and with a positive polymerasechain reaction assay for Candida albicans49.2% of the time. Diagnostic accuracydid not improve with higherlevels of experience.

The inadequacy of level I wetmount examinations is well illustratedby BES/BV. The accepted criteria forthe diagnosis of BES/BV are demonstrationof clue cells (level I criteria)supplemented by a positive volatileamine test, a pH greater than 5, andan absence or relative absence of lactobacilli.Failure to use all of the levelII criteria can mask for a prolongedperiod the high probability of a concomitantsexually transmitted diseasewhen inflammatory cells are present.3

The health care needs of womenare best served by an accurate diagnosis.To lessen the possibility oftherapeutic failures as a result of misdiagnosis,residents in primary carespecialties must be required to learnhow to monitor and interpret wetmount/KOH analysis.


REFERENCES:1. Monif GRG. Infectious Diseases in Obstetrics andGynecology. 2nd ed. Hagerstown, Md: Harper andRow; 1982.
2. Ledger WJ, et al. Infect Dis Clin Pract. 2000;9:28-29.
3. Joesoef MR, Wiknjosastro G, Norojono W, et al.Coinfection with chlamydia and gonorrhoea amongpregnant women and bacterial vaginosis. Int J STDAIDS. 1996;7:61-64.
4. Monif GRG. Interpretation of Wet Mount Preparations.Omaha: IDI Publications; 1995.