Some people with diabetes might seem to have good blood sugar control based on standard tests, but if their red blood cells don’t live as long, the test could be misleading — and nearly 1 in 3 of these patients might actually have worse blood sugar levels than the test shows.

If you have type 2 diabetes and your red blood cells don’t live as long—less than 75 days—your A1c test might not give a true picture of your blood sugar control, because the test could show lower numbers than reality.

Lots of people with type 2 diabetes have red blood cells that don’t live as long as usual, and because of that, their A1c blood sugar test might show lower numbers than reality — meaning the test could be misleading for many.

If someone with type 2 diabetes has good HbA1c numbers but their red blood cells don’t live as long, their blood sugar might actually be higher than the test shows — meaning the test could be giving them a too-rosy picture of their sugar control.

Even when blood sugar averages look good on a diabetes test, people with shorter-lived red blood cells might still have higher actual sugar levels throughout the day.

If someone with type 2 diabetes has red blood cells that don’t live as long, their A1c test might be giving a lower number than their real blood sugar levels — meaning the test could be misleading for them.