Q-PCR and LA measurement by visual signal strength categories. A total of 143 viral load measures for all five HPV types (HPVs 16, 18, 31, 33, and 52) by Q-PCR (A) and LA densitometry (B) are shown stratified by visual signal strength categories (Neg, no signal; EW, extremely weak; VW, very weak; W, weak; M, moderate; S, strong). Similarly, viral load measures based on Q-PCR (C) and LA (D) are shown for HPV16 separately. Total numbers in each visual signal strength category are indicated together with median values and interquartile ranges (in parentheses).