Alternate Site Testing

Alternate Site Testing

Alternate Site Glucose Testing

Reduce testing pain and stop sticking your fingers!

Alternate Site Testing has been approved by the US Food and Drug Administration (FDA). The term "alternate site testing" (AST) means using parts of the body other than the fingertips to obtain a blood sample for blood sugar testing as a part of your self-monitored blood glucose (SMBG) diabetes management process. With an approved glucose testing meter you can check your blood sugar without the pain associated with the finger stick. The FDA reports that many newer design glucometers can use blood from other areas of the body besides the fingers which can reduce your discomfort. This alternate site testing (AST) methodology should be carried out carefully and only in certain circumstances. It is important to discuss testing with your physician and to follow the manufacturer's instructions to get the most accurate blood glucose test results.


Self-monitoring of blood glucose is an important part of the treatment plan for people with diabetes. It helps you develop your individual blood glucose profile, so you and your health care team can plan your particular diabetes management regimen. It provides you with the ability to make day-to-day treatment choices with meals and physical activity as well as with oral agents and insulin, and it helps you recognize and understand the effect of lifestyle and diabetes medication on your diabetes control.

  • Can blood sample size affect the result? (click for answer)

    Yes, blood sample size can affect the testing result. Always follow the instructions in your Owner's Manual for applying blood to the test strip and make sure that the blood sample has completely filled the confirmation window of the diabetic test strip. You may download owner’s manuals for the diabetic test meters we offer in the glucose test meter section of the site. 

  • Which result should be used to determine how much medication to take if there is a difference between a forearm test and a finger stick diabetic test? (click for answer)

    If there is a difference between a result using a sample from the forearm and a result from a finger stick test, use the result from the finger stick.

    * Under certain conditions, blood glucose test results obtained using samples from the forearm may differ significantly from fingertip samples.
    * The conditions in which these differences are most likely to occur are when your blood glucose is changing rapidly, such as during the 2 hour period following a meal, insulin dose or physical exercise.
    * When your blood sugar is falling, testing with a fingertip sample may identify a hypoglycemic (low blood sugar) level sooner than a test with a forearm sample.

    Remember to consult your physician with any questions you may have regarding your medication.

  • How would I know if I have hypoglycemia unawareness? (click for answer)

    Have you often obtained blood glucose readings below 55 mg/dL without any of the usual symptoms of hypoglycemia (sweating, tremors, rapid heartbeat, nervousness, extreme hunger)?

    * Have you had episodes of impaired thinking?
    * Have others observed you in situations where you appeared pale, tired, confused or acting as if you were in slow motion?
    * Have you acted irritable or forgetful, even though you physically felt fine?
    * Have you had difficulty managing a hypoglycemic episode, which required the assistance of others?
    * Have you ever had a seizure or loss of consciousness without any warning signs?
    * Do you try to maintain very tightly controlled blood sugars (often running below 90 mg/dl)?
    * Have you had frequent episodes of hypoglycemia?
    * Have you had diabetes over 20 years?
    * Have you had a recent episode of severe hypoglycemia?

    If you answer yes to any of these questions, please discuss this situation with your physician.

  • What do I need to know about forearm glucose testing? (click for answer)

    You can choose fingertip, forearm, palm, thigh, calf or foot testing with multi-site Blood Glucose Monitoring Systems. Forearm testing may mean less pain because your arm has fewer nerve endings than your fingertips. Before you try testing on your forearm, read your owner's manual to understand when and how to forearm test and talk to your health care professional.

    When to forearm test

    Although forearm testing can give sensitive fingertips a break from testing, forearm testing should only be used at the right times. Studies show that test results using samples taken from the forearm may differ from fingertip samples when blood glucose is changing rapidly, such as within two hours after a meal, an insulin dose or exercise.

    * Only use forearm testing before a meal, an insulin dose or physical exercise, or two hours after a meal, an insulin dose or exercise.
    * If you test within two hours after a meal, an insulin dose or exercise, you should test from your finger.
    * When blood glucose is changing rapidly, fingertip samples show these changes more quickly than forearm samples.
    * When your blood glucose is falling, testing with a fingertip may identify a hypoglycemic (low blood sugar) level sooner than a test with a forearm sample.
    * You should use fingertip testing whenever you have a concern about hypoglycemia (insulin reactions), such as when you drive a car, particularly if you suffer from hypoglycemic unawareness (lack of symptoms to indicate an insulin reaction), since forearm testing may fail to detect hypoglycemia.
    * If the results from the forearm do not match how you feel (high or low), test from the fingertip and use those results.

    Some tips to help you successfully test on your forearm:
    * Before you test, rub your forearm.
    * Choose an area that's free of hair and obvious veins.
    * When using the lancet device, use the clear cap. This lets you view the test site so you can see when you have an adequate blood sample from the forearm.
    * Hold the lancing device on the forearm for 5 seconds to allow an adequate blood sample to collect on the surface. The clear cap allows you to see your sample.

  • How do I perform an alternate site test? (click for answer)

    Follow these simple steps in order to achieve an accurate blood glucose test result:

    1. Vigorously rub the alternate site test area until it is warmed from increased blood flow to the surface of your skin. 
    2. Carefully clean your skin and lance the alternate test site using your lancing device
    3. Touch the diabetic test strip to the blood drop in order to collect a sample for testing.

     For more information on how to perform a blood glucose test, please refer to your user's guide for your blood glucose meter.

  • When is testing on the finger preferred? (click for answer)

    It is important to note that when your blood glucose is changing rapidly, there may be a difference in the glucose readings between your finger and other test sites, like the forearm, upper arm, thigh, calf, and other areas of the hand. Because blood flow to the finger is three to five times faster than other alternate sites, blood samples from the finger may show changes in your glucose sooner than other parts of your body.

    The possible difference in glucose readings between the finger and other alternate testing sites could delay your detection of hypoglycemia. Abbott Diabetes Care, the maker of FreeStyle Freedom Lite glucose meters, recommends that this potential difference in glycemic test results is due to differences in blood flow and can be minimized by the alternate test site before drawing a blood sample.

  • Why is alternate site testing less painful? (click for answer)

    Your fingertips, the key area for your sense of touch, are full of nerve endings (receptors), which make the fingertips feel pain more readily. Other body sites such as the forearm have fewer nerve endings per square inch than the fingertips, thus resulting in less pain. This can make alternate site testing with an approved meter virtually pain-free. A consumer survey of US diabetes patients conducted by NOP World Roper a few years ago, showed that of patients who tested using alternative sites, 70% perceived alternate site testing to be less painful.

    Alternate site testing offers the most test sites available and gives those who have occupations or hobbies that require extensive use of their fingers another option to fingertip testing.

  • Testing on the finger is recommended if... (click for answer)

    If you think your blood glucose is low (hypoglycemia) or if you have a history of hypoglycemia unawareness (no symptoms when your blood glucose is low). Blood glucose that is too low must be treated right away. If you have symptoms such as weakness, sweating, nervousness, headache or confusion, follow your doctor's recommendation for treating hypoglycemia. The US Food and Drug Administration(FDA)  advises patients to only use blood taken from their fingertips for blood glucose testing if any of the following circumstances apply:


    • you have just taken insulin 
    • you believe that your blood sugar is low 
    • you become hypoglycemic without being aware of symptoms
    • the meter test results do not agree with the way you feel 
    • you have recently eaten 
    • you have recently exercised 
    • you are feeling ill 
    • you are under stress 

    Additionally, the FDA advises that you should never use results from an alternative sampling site to calibrate a continuous glucose monitor (CGM), or in insulin dosing calculations.

  • With alternate site testing where can I test? (click for answer)

    Most commonly you will test on your fingertips or forearm. With some Alternate Site Test Meters, a blood sample test can be performed on the fingertips, forearms, upper arms, thighs, calves, and hands. You should always consult your health care professional for acceptable sites for your testing needs.

  • Why are there differences between forearm and fingertip results?(click for answer)

    Blood sugar concentrations in the body vary due to different rates of glucose utilization by different body tissues. The varying rates of glucose utilization may be due to varying amounts of muscle and fat tissue in parts of the body, muscular activity and variations in blood flow. It is not known which of the sites reflects blood glucose values of greatest physiological significance with regard to managing diabetes. However, if a person does experience differences greater than 20% between forearm and fingertip, the fingertip reading should be relied on as this is generally the location that has been used to establish doses of medication. For more information please refer to your meter manual.

  • What is the percentage of difference when comparing results from the forearm to a result from a finger stick test result? (click for answer)

    For tests before meals, or 2 hours or more after a meal, the forearm and finger results should be within 20% of each other. For more information please refer to your meter manual.