Mistake in Calculating the Positive Predictive Value.

Dear Editor-in-Chief

As I read the study by Bakhtiari et al. (1), I noticed that they miscalculated the positive predictive value. They indicated that the positive predictive value of the PCR assay was 100%. But when I placed the values on the table and calculated the positive predictive value of the PCR assay, I found it 83.3%.

Table 1

	Culture (+)	Culture (-)	Total
PCR (+)	35	7	42
PCR (-)	0	333	333
Total	35	340	375