Sometimes, a slight change in how you do something makes all the difference in the world. At least, that’s what a new study suggests.

Researchers at the University of Pennsylvania School of Veterinary Medicine (Penn Vet) found a way to obtain more accurate measurements from glucometers by using blood plasma or serum rather than whole blood. The findings were published this month in the Journal of the American Veterinary Medical Association (JAVMA).

“It’s a simple study, but it has changed the way we do things,” said Rebecka Hess, DVM, B.Sc., senior author and Professor of Internal Medicine at Penn Vet.

With their owners’ consent, researchers enrolled cats and dogs that were going to have blood drawn for another purpose in the study. The researchers obtained 96 blood samples from 80 dogs and 90 blood samples from 65 cats.

The researchers tested each sample in both the glucometer and, as a control, a biochemical analyzer, which is more accurate but more expensive in time, cost, and the amount of blood required.

The Penn Vet researchers found that testing either blood plasma or blood serum in the glucometer gave results that were nearly the same as those given by the biochemical analyzer and were more accurate than whole blood.

Based on these results, Ryan Hospital changed its practices to use blood plasma or sera rather than whole blood when measuring blood glucose with a glucometer.

“It’s widely known that glucometer readings come with a degree of inaccuracy, and until now we’ve just lived with it,” added Hess.