[358] Evaluation of HPV Positivity Rate as a Quality Assurance Measure for a Cytopathology Lab.

Anne Das, Amar Agadi, Shagufta Khan, Fred Lucas. University of Cincinnati College of Medicine, OH; Tristate Laboratories, Cincinnati, OH

Background: With the advent of validated techniques for HPV testing, a new metric to monitor the accuracy of ASCUS(Atypical Squamous Cells of Undetermined Significance) diagnoses has been introduced. An application of this metric in our lab with a mixed demographic offers a new perspective to the existing studies. The CAP QProbes study of 68 institutions classifies HPV positivity rates for ASCUS cases by different demographic metrics including type of institution and patient age. The overall HPV positivity rate for their study, including teaching and non-teaching institutions, is 43.74% (SD of 17.77%).
Design: We compared the results of 814 reflex HR-HPV(High Risk HPV) tests over a 6 month period in 2010 for ASCUS diagnosis cases to the national data reported by the ALTS trial and the CAP QProbes study. The purpose of this comparison was to evaluate whether our mixed patient demographics contribute to the deviation in our HPV positivity rate.
Results: 1. Table below shows that the HPV positivity rates (HPR) of university clinics(UC) and suburban/peripheral clinics (PC) cases deviate from the ALTS and CAP QProbes study as well as from each other.

Positivity Rate by Institution
 UCPCWTD AVG UC/PCALTS TrialCAP QProbes study
HPV positivity rate %51.525.22950.643.74
# of cases127687814348868 institutions
HPR in % calculated as: ( # of HPV (+) cases / Total # of ASCUS cases) x100

2. Age distribution of the two populations is not uniform. 35% of the UC cases are within the 21-25 age group compared to only 15 % for the PC. The UC mean age is 32 (median of 28, SD of 11). The PC mean age is 38 (median of 37, SD of 13)
3. Comparison of HPR for 4-year categories of ages (<=20, 21-30, 30-40, 40-90) for UC, PC, the combined UC/PC entity, and CAP QProbes show that the HPR trends lower in an almost linear fashion up to age 40 and then stabilize or decrease slightly in most cases.
Conclusions: Our study evaluated a new parameter- impact of demographics on HPR which is in addition to the parameters reported in CAP QProbes. The results show that our institutions (UC and PC), in spite of the influence of demographics lie within 1 SD of the CAP QProbes study (acceptable range suggested by CAP QProbes is 2SD).
Although this degree of variability is acceptable, we want to explore if HPR in individual hospital settings can be utilized to achieve a more precise QC and can serve as a tool to monitor individual pathologist performance.
Category: Cytopathology

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 105, Tuesday Morning

 

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