After Covid-19 test duty, GeneXpert machines revert to TB testing

With Covid-19 cases declining, the Tuberculosis (TB) wing of the Health department has been asked to utilise all the remaining CBNAAT cartridges available for Covid-19 testing and from now on use the GeneXpert machines for testing TB samples as was done before the pandemic.

The state resorted to using the machines for testing Covid samples when the pandemic began. So far, 29,599 Covid samples have been tested using CBNAAT method. There are eight to nine government Covid testing labs that have GeneXpert machines in the state.

Dr Ramesh Reddy, joint director, TB, Health department, said, “Cartridges for GeneXpert machines are supplied by the Government of India. We cannot procure them locally. Around 3,000 cartridges arrived two months ago. Further supply will not come. We cannot do anything. We are left with 500 cartridges to test Covid samples.”

Rapid antigen/RTPCR

Now, the labs have to use rapid antigen method and RTPCR machines for Covid-19 tests.

Eliminating TB

“We have received guidelines that we have to use TrueNAT and CBNAAT machines to test TB samples as we have a goal to eliminate TB. If we use the machines for Covid testing, we cannot do TB testing. Even though Nimhans did not ask for the cartridges, we gave it to them, to exhaust them. Active case finding is underway for TB and door-to-door survey will be done.”

The Belagavi Institute of Medical Sciences (BIMS) started CBNAAT testing on May 6 and has so far tested 286 Covid samples with the technology.

Quick tests for emergencies

Dr Mahantesh Parande, HoD, microbiology, BIMS, told DH, “We use CBNAAT only in emergency situations, because we have shortage of cartridges. We last got 360 cartridges from the Health department on November 10. The advantage of using CBNAAT is, in cases of emergency surgery, we can get the Covid test result in three hours, while RTPCR takes eight hours for a cycle.”

While TrueNAT results come in one-and-a-half hour, only four samples can be mounted at one go. The GeneXpert system is available in a one, two, four, and 16-module configuration.

Gadag Institute of Medical Sciences (GIMS) started CBNAAT testing on April 24. Dr Mahesh Baragundi from GIMS said, “We tested 193 Covid samples with CBNAAT and then stopped, as despite repeated requests, we were not supplied cartridges.”

Dr Channamma Katti from the Vijayapura district hospital said, “We have tested 200 Covid samples with CBNAAT so far. We could not use more than 400 cartridges supplied more than two months back, because our GeneXpert machine was taken away by the Health department for TB testing.”