. Author manuscript; available in PMC: 2009 Aug 1.

Published in final edited form as: J Virol Methods. 2008 Jun 24;151(2):298–300. doi: 10.1016/j.jviromet.2008.05.017

Table 3.

A comparison of the mean prevalence of all HPV genotypes detected and all carcinogenic HPV genotypes detected from all time periods versus the control. Mean prevalence is calculated by summing all infections detected within group and dividing by the total number of possible infections detected, assuming independence of infections. For example, 213 HPV genotype-specific infections were detected in the specimens stored for 6 months. The HPV genotyping assay detects 19 HPV genotypes for a total of 2,717 possible HPV genotype-specific infections, yielding a mean prevalence of 213/2,717 or 7.84%.

Storage Time	N (specimens)	Total Number of Infections	Mean Prevalence	Total Number of Carcinogenic Infections	Mean Prevalence
6 Months (pH = 12–13)	143	213	7.84%	180	8.99%
4 Months (pH = 12–13)	143	193	7.10%	164	8.19%
2.5 Months (pH = 12–13)	143	186	6.85%	161	8.04%
Control (1 Month) (pH = 6–7)	142	192	7.07%	171	8.60%

p = 0.5, Pearson χ²; p_trend = 0.3 (all HPV genotypes)

p = 0.7, Pearson χ²; p_trend = 0.6 (carcinogenic HPV genotypes)