Pathologist Questions Diabetes

Home diabetes testing device and lab report show different results. What is more accurate?

I bought a new diabetes testing machine at home and I have been checking my sugar levels with it every day. However the lab reports and the home test numbers don’t seem to match. What according to you is more accurate?

6 Answers

I would say the lab's because their equipment is constantly being monitored. The home equipment just gives you the opportunity to just generally monitor your progress. If you feel poorly and your home device says your sugars are ok, go to the lab for testing after discussing it with your doctor since they would have to be the one to issue the order for the lab work.

RB Thomas, MD
Lab report is always more accurate as these are done on proper venous blood samples and tests are done on quality controlled machines. Most devices test glucose levels from finger prick (capillary blood) which may not be the best sample for accurate results. Good devices should not differ by more than 10-15% from lab reports.
The lab test have more accurate results. Labs have to abide to strict guidelines to be able to safely perform and interpret these test. Diabetes testing devise is also not technically maintained.
Home blood glucose testing, measures glucose in a drop of whole blood, while the clinical laboratory measures glucose in the serum.
Serum, to put it simply, is the fluid of the blood minus the red blood cells. Under well controlled circumstances, whole blood glucose is usually higher than serum glucose about 5 to 10 %.
As I stated, under well controlled circumstances, means that the home blood glucose testing meter must be well calibrated with two points glucose standards and the readings of those standards must be within the mean and standard deviation of the stated values.
The clinical laboratory, on the other hand,always perform calibration and runs quality control materials on a regular basis as mandated by the accrediting agents.
In general, home blood glucose testing is simply "Glucose Monitoring", which provide a close enough picture of the patient's diabetes status.
I hope this provides a simple answer to your question.
I recommend checking your sugar level from another lab and compare them before you decide which one is more accurate.
There can be many variables that determine the blood sugar levels. These include, the nutritional status (fasting/ non-fasting), prior physical activity, time of day test performed, technique, etc etc., before the test is performed. These factors apply to both home device and outside lab testing. In general, outside lab test results are usually more accurate although the newer home testing devices are pretty accurate too.