Letter to the Editor

Iranian J Publ Health, Vol. 42, No. 12, Dec 2013, p. 1480

Mistake in Calculating the Positive Predictive Value Süleyman UTKU UZUN Dept. of Public Health, Faculty of Medicine, Pamukkale University, Turkey *Corresponding Author: Email: [email protected] (Received 10 Sep 2013; accepted 15 Sep 2013)

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 PCR (+) PCR (-) Total

Culture (+) 35 0 35

Culture (-) 7 333 340

Total 42 333 375

Reference 1.

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R Bakhtiari , MM Soltan Dallal , JF Mehrabadi , S Heidarzadeh , MR Pourmand. Evaluation of culture and pcr methods for diagnosis of group B Streptococcus Carriage in Iranian pregnant women. Iranian J Publ Health, 2012, 41(3):65-70.

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