Faulty thermometers could send Kenyans into quarantine

"Your temperature is too high, we cannot allow you in," a security guard says at a Nairobi mall before he calls the health emergency services.

The thermal gun reveals a temperature of 39 degrees, which means the shopper is extremely sick, probably from a coronavirus infection.

The thermal gun or infrared thermometer is now the standard device used across Kenya to test people for fever, a possible symptom of Covid-19. 

A second take with a different thermal gun reveals the shopper has a normal body temperature of 36.7 degrees.

The generally accepted body temperature ranges between 36.1 degrees to 37.2 degrees and anything above that can send you into quarantine. 

"In any instrument, there's a likelihood of deviation from the correct measurements after usage over time," director of metrology and testing at the Kenya Bureau of Standards Dr Henry Rotich says.

He says a thermometer used frequently every day will experience slight changes in a given period and should be calibrated at the right time.

"This allows the user to maintain accurate, reliable and consistent results when making temperature measurements."

Last week, Kebs urged all users to ensure their thermometers are calibrated regularly. 

Since the Covid-19 was confirmed in Kenya on March 13, thousands of thermal guns have been imported as the first diagnostic tools for the disease. 

Dr Rotich explains that all equipment need regular calibration as advised in their operation manuals.

"By law, we're the custodians of primary measurements and standards, and we are the ones who calibrate all equipment," he says. 

"When a thermal gun is not calibrated at the right time of use, it can give skewed readings."

Calibration is the process of verifying that the readings of an instrument match that of a standard.

If a device is not within a specified tolerance, it is adjusted so that it is within the bounds of the specification.

"Sometimes even a new instrument should be calibrated," he explains.  

Thermal guns are equipped with an infrared sensor that can measure surface temperature without contact with a person’s skin.

Users just need to hold them about three to 3.5 centimetres from someone’s forehead to obtain the correct temperature. 

"Temperature check is the first line of diagnostics, which is why the instrument should be accurate. The decision for the next steps is based on that preliminary diagnosis," Rotich says. 

Some require calibration every month, others every six months or one year, according to instructions by the makers.

Kebs’ calibration laboratories are at par with South Africa's and Egypt's and are, therefore, considered among the best in Africa. 

"We have mutual recognition agreements with them and others in Europe, which means products with our certificates can freely be traded in those territories," he says. 

Onesmus Munyithya, the metrologist at the calibration laboratory, says thermal guns are calibrated using the 'black body furnace' equipment.

"The process for each thermal gun takes about 40 minutes to one hour. We then issue a calibration certificate to the user," he says. 

He explains that users of such thermometers must be trained properly and select the right mode. 

An environment mode can, for instance, give readings of up to 1,000 degrees, impossible in the human body. 

"The user manual is very important," he explains, "It shows the right conditions for using the instrument and when it's due for calibration."

Dr Rotich explains an instrument that is not calibrated also runs the risk of missing out people who are sick. 

 A restaurant server could also cause worry, ostracise a healthy person and even lead to unnecessary quarantine just because they used faulty equipment.

"The whole point is to protect you as a person and others because, with the correct measurements, we can make the right decisions," he says.

Edited by R.Wamochie