Is a single measurement of ASO or Anti-DNAse B enough?
Actually no. titers have to be measured at two points (typically a week apart). ASO is typically measured at 4 and 5 weeks from the date of suspected infection and Anti-DNAseB measured at 6 weeks and 8 weeks from the suspected event. The two data points are needed to look for a rise. Absolute values are not as important as the rise/fall of the titer. For this reason it is important that both samples are done by the same lab. In the absence of having two titers, many labs use a measure known as the \”upper-limit-of-normal\”. This value is helpful if the measured value is significantly higher than the upper limit. If it is lower than the ULN, then typically two samples are needed to look at the slope/trend.
