Alternate Site testing (AST)
What is Alternate Site Testing (AST)?
The most common site for blood glucose testing is the finger tips. For some people though, fingerpricking can become painful or inconvenient over time. Now some meters such as the Accu-Chek Go make it possible to test from other sites - the forearm, thigh and heel of the thumb. This allows for more choice and flexibility about where to test.
Ensuring Accurate Results
Glucose results from AST can be different from a fingerprick test. The reason for this is that the fingertips have a much higher blood flow than other sites, meaning changes in blood glucose will be seen earlier. It can take up to half an hour to detect increases or decreases when using alternate site testing. Results can vary from person to person, site to site and time to time, so care should be taken when interpreting them*.
The following situations may cause a difference between AST and fingerprick test results:
- A recent meal
- If you have an infection or illness
- If any of your tests have recently been outside the normal range
- If you have just taken insulin
- Recent exercise
- A history of recurrent hypoglycaemia
* Ref. Jungheim, K et al; Diabetes Care, 25(6):956:2002.
How to Achieve an Adequate Sample
You may find that getting an adequate sample from another site other than the fingertip a little more difficult, so here are some tips to help with successful AST testing:
- Only use a meter recommended for AST (check the instruction manual to be sure)
- Use a lancet device suited to AST (such as Accu-Chek Softclix with AST cap)
- Dial up the highest number on your lancet device for the first try (remember it won't hurt nearly as much as a fingerprick)
- Vigorously rub the site to stimulate blood flow
- Lance the site but keep some pressure on it with the device until you see a drop of blood start to form
It may take a few tests to get the technique right and you may want to do an AST and a fingerprick test at the same time just to compare results.
If you decide to use AST you should regularly make sure that your AST results match your fingerprick test results AND be sure the AST results confirm how you are feeling.
Until you discuss the suitability of AST with your healthcare professional, please continue to use only fingerprick test results.