Checking Beyond The Fingertip
This is the final post in the series the ABCs of Testing
Nothing has improved the quality of life for people with diabetes as much as the ability to check and control blood sugar. Still, over time, finger pricks can get pretty tiresome. That's why there's been a lot of discussion of the value of testing blood glucose levels at other parts of the body.
What sites can be checked?
If your doctor says it's okay, you may be able to take a blood sample from your palm, forearm, upper arm, thigh or calf.1 Because these can be less painful,2 doctors hope people will test more often and, ultimately, gain better control.
Is alternate site testing for everyone?
AST, as it's known for short, is best for people who have fairly consistent blood sugar levels. If that describes you, talk to your doctor. If using another site is a good fit for you, it's only suited to routine tests when your blood sugar is stable, such as before eating, after fasting or before bed.
When is it NOT a good idea?
Testing another site should never be used when your blood sugar may be rising or falling rapidly. Studies suggest that, because there are fewer capillaries in the other sites, test results may lag by as much as 15 or 30 minutes behind a fingertip test. If you're headed for a blood sugar low, you know those 15 minutes can be critical.3
To recap, don't test from an alternate site...
- Following a meal
- After exercising
- When you're sick
- If you think you might have low blood sugar
Can I use my current meter?
AST is approved for use with a variety of blood sugar meters, but check with the manufacturer to be sure.
Are AST checks different?
- Our lancing devices require a different cap for alternate site testing, so check the owner's manual for yours before you start. You may also find that you need to prick a little deeper, since the skin may be thicker than on your fingers.
- Try different sites on your body until you find one that comfortably provides a large enough drop of blood to run a test. Remember to rub the skin first to get things moving in there.3
- Then, once you choose a site, stay with it. You can't rotate sites like you switch from finger to finger. If you test your forearm, you should always test your forearm.
Finally, if your alternative site test doesn't match the way you feel, double-check with a fingertip test. It's still the most reliable result you can find. For more detail, read Children with Diabetes' deep dive into AST.
1Talk with your doctor before deciding if alternate site testing is right for you.
2Freitas RA. Nanomedicine, volume I: basic capabilities. Georgetown, TX: Landes Bioscience; 1999. Available at: www.nanomedicine.com/NMI/220.127.116.11.htm. Accessed January 23, 2012.
3Bina DM, et. al. Clinical impact of prandial state, exercise, and site preparation on the equivalence of alternative-site blood glucose testing. Diabetes Care. 2003; 26:981-985. Available at: care.diabetesjournals.org/cgi/content/full/26/4/981. Accessed January 23, 2012.