Tested negative or positive? Transparency takes a hit in Kerala

Aswin J Kumar | TNN | Updated: May 3, 2020, 12:01 IST

Confusion arose over the accuracy of test results in the case of two patients as their samples were tested negative even within 24 hours of hospital admission.

Confusion arose over the accuracy of test results in the case of two patients as their samples were tested neg...Read More

THIRUVANANTHAPURAM: The state government continued to put a lid on the actual case status of two patients who were admitted to Medical college hospital, after their samples had tested positive for Covid-19 at Rajiv Gandhi centre for bio-technology. Confusion arose over the accuracy of test results in the case of two patients as their samples were tested negative even within 24 hours of hospital admission.
Repeated tests also yielded negative results in medical college and another centre following which samples were also sent to NIV Alappuzha for revalidation. While state health department did not reveal the test results from NIV, sources confirmed that the results are negative. When TOI checked with health authorities in Kanyakumari, they said that the test results of 68-year-old man from Tamil Nadu have been tested negative at NIV Alappuzha and they have received an unofficial communication from Kerala on this regard.
Given the repeated negative results after the first positive, the health officials believe that the two active cases presently in Medical college could be true negatives. Usually testing results in four types of scenario; true positive where a person with Covid-19 tests positive for the disease, false positive; a person without Covid-19 tests positive for Covid-19, false negative; a person with Covid-19 tests negative for Covid-19 and true negative; a person without Covid-19 tests negative for Covid-19.
“There is always a factor called pre-test probability in which doctors look for patterns in clinical symptoms, other factors to anticipate chances of infection. In addition to test results from the machine, we also have to go by pre-test probability. In cases where we think it is a weak positive; either we collect more samples and do two tests; a retest on first sample and a new test on sample collected again. When both yield same result, we can confirm and declare the result,” an official said.
When chief minister Pinarayi Vijayan was quizzed about two different results for same person during his daily news conference on Saturday, he sounded vague in his reply. “The first test was doubtful; a retest was done to allay the doubts. The retest yielded accurate results,” he said without making it clear whether it was a case of false positive or not.
Dr Rajan Khobragade, principal secretary, health department ruled out any confusion; however, when asked how two states could interpret different results for the same person; he said that the first test can be misleading. He also said that the test becomes negative if the person is in recovery. However, the patients were tested negative barely within 24 hours of hospital admission for Covid-19, which hardly gives any time for recovery and that one of the patients had to be admitted to Covid-19 ICU.
M Radhakrishna Pillai, director, RGCB said that the tests were very clear, however it was unclear whether there was an error in sampling. “We didn't do retest as it was unnecessary. Our results are very clear, in that sample it tested positive. There is always a positive control and negative control and when both work you know that the test is correct. Whether it was an error in sampling we don't know because samples were received from the hospital,” he said.
Meanwhile, the 68-year-old person was shifted from ICU to room on Saturday where his son has been staying since April 29. The other person is also under treatment in a room with his wife opposite to the room where Tamil Nadu native stays. Covid-19 patients are not allowed by standers generally, however medical college authorities said that in these cases, the patients are dependent, hence by standers are allowed.