Medics share views about negative, positive test

The conflicting test results of Samoa’s first suspected coronavirus case is being discussed among health professionals in the territory and elsewhere.

Samoa Prime Minister Tuilaepa Sailele announced at a press conference yesterday that a swab of the left nostril of a returning Samoan sailor tested negative for coronaviruys and one of his right nostril showed a positive result.

A blood sample of the sailor is to be sent to New Zealand this Friday for more testing.

Dr Aifili John Tufa of the Department of Health quoted the CDC Regional Field Officer, saying the results are most likely a “false negative.”

He said the GeneXpert machine that Samoa used for the test rarely produces false positives.

He further explained that GeneX is a high sensitivity machine. But specificity is somewhat lost when the person being tested is not symptomatic and does not have symptoms.

The epidemiologist suggests that this case be treated as a true positive coronavirus case. However, he explained it doesn’t necessarily mean that the sailor is infectious.

He also pointed out that if the sailor had the virus previously, his body may still be shedding RNA materials which are being picked up by the test.

Dr Tufa said what Samoan authorities are doing now, that is isolating the sailor for 10 days is exactly what is recommended.