*BRAZIL REVISES GUIDELINES FOR DIAGNOSING MICROCEPHALY TO AVOID FALSE POSITIVES
*REGISTRY ESTABLISHED IN OCTOBER USED LAX MEASURESMENTS, OVERDIAGNOSED MICROCEPHALY
*WAS THE MICROCEPHALY SURGE REPORTED IN BRAZIL DUE TO THESE FAULTY GUIDELINES?
RIO DE JANEIRO — Brazilian officials said on Wednesday that they had tightened the guidelines used to determine when babies have been born with abnormally small heads, a step taken in part to reduce the number of false positives for microcephaly, a condition that can lead to brain damage.
The change, expected for more than a month, came as a result of recommendations made by Brazilian medical and epidemiological experts as the country continues to grapple with an outbreak of the Zika virus, which has been linked to a surge in cases of microcephaly.
The changes were also announced in the wake of new interim guidelines issued by the World Health Organization.
The Brazilian government will now require health professionals to report suspected microcephaly cases when a male infant’s head at birth measures 31.9 centimeters or less and a female’s measures 31.5 centimeters or less, in line with the recently announced interim W.H.O. guidelines for reporting microcephaly.
The previous cutoff was 32 centimeters, or just over 12.5 inches, for both sexes.
When the Health Ministry established its registry last October, any child whose head measured 33 centimeters or less was considered at risk, based on a combination of adjusted international standards. By December, the ministry realized that many babies it was tracking had smallish heads but were developing normally, so it adjusted the definition, to 32 centimeters.