Objectives:

To determine the efficacy of a molecular test in the diagnosis of Streptococcus agalactiae or beta hemolytic group B (SGB); in Samarian pregnant women.

Methods:

Evaluative study with no experiment design; carried out in a population of 100 women between 35 and 37 weeks of gestation, from which a probabilistic sample of 80 patients was calculated, with a confidence level of 95% and margin of error of 5%. The test used for the evaluation of effectiveness was the real-time polymerase chain reaction (PCR) which allows to amplify specific sequences of deoxyribonucleic acid (DNA) more than one billion times, compared with a routine test using the Chromogenic (CHROMagar) guiding medium. The ethical criteria defined for human studies were respected.

Results:

Average age of the population 27 years; with the application of the molecular test (real-time PCR) 42/80 patients were detected colonized by GBS, corresponding to a positivity of 52%, a test that showed sensitivity of 65, specificity 93, PPV 91.2 and NPV 73.1; whereas with the comparison test the positivity level was 5% (4/80), with a sensitivity of 6.2, specificity of 3, PPV 8.8 and NPV 26.9.

Conclusions:

The real-time PCR test, as molecular test used, showed greater efficacy when diagnosing cases of group B beta hemolytic Streptococcus agalactiae (GBS), when confronted with the routine test.

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