TABLE 3.

Comparison of IDI-MRSA assay, GenoType MRSA Direct, and selective MRSA agars in the detection of MRSA with nasal swabsa

TestNo. of positive samplesbNo. of negative samplesbNo. of inhibited samplesSensitivity (%)Specificity (%)PPV (%)NPV (%)
Molecular detection tests
    IDI-MRSA5347194949494
    GenoType MRSA Direct3959370969573
Selective agars at 24 h
    MRSA ID406172959575
    MRSASelect376468989773
    CHROMagar MRSA465575888676
Selective agars at 48 h
    MRSA ID604181657275
    MRSASelect564577697373
    CHROMagar MRSA524979798078
  • a PPV, positive predictive value; NPV, negative predictive value.

  • b True positive (n = 53) and true negative (n = 48) samples, defined as described in the text.