Skip to content
My WebMD Sign In, Sign Up

Diabetes Health Center

Font Size

Accurate Blood Sugar Readings Are at Your Fingertips

By
WebMD Health News
Reviewed by Gary D. Vogin, MD

July 9, 2001 -- Pricking your finger every day to test your blood for its sugar content is the painful reality of people with diabetes. Recently, relatively pain free devices that take blood from the forearm have become available, but are they accurate?

People with diabetes don't produce enough of or respond appropriately to a hormone called insulin, which is needed to control the level of sugar in the blood. As a result, many diabetics must routinely check their blood sugar levels to make sure they're within a healthy range.

Checking blood sugar levels has, until recently, involved taking a painful finger prick. Now manufacturers are answering the need for a less painful way of testing for sugar in the blood by developing devices that require only a very tiny amount of blood from an alternate site on the body, namely the forearm.

New research, however, has called into question the accuracy of blood sugar testing from the forearm. Author of the study, Theodor Koschinsky, MD, PhD, tells WebMD that during rapid blood sugar changes "clinically relevant differences" occurred in blood sugar readings taken from the forearm and the fingertip. He is from the German Diabetes Research Institute and an associate professor at the University of Dusseldorf in Germany.

Koschinsky and his colleague gave men with diabetes a high sugar breakfast followed by a strong insulin treatment in order to make their blood sugar levels go very high then very low. They used both a finger prick device and a forearm device to check their blood sugar levels at several points during the study.

When the amount of sugar in the blood was rising or dropping rapidly, only the finger prick testing accurately caught these rapid changes. It took about 30 minutes for the forearm values to catch up to those reported by the finger prick tests. This research was presented recently in Philadelphia at the annual meeting of the American Diabetes Association.

C. Kurt Alexander, MD, CDE, FACP, has also performed research on the accuracy of forearm vs. finger prick blood sugar testing for Roche Diagnostics, the makers of blood sugar testing devices. He also found that, "a drop of blood out of your forearm is not [always] the same as a drop of blood out of your fingertip."

In Alexander's research, forearm testing was most likely to be inaccurate during the two hours after eating a meal, and there was no consistency as to whether the forearm reading was lower or higher than the finger prick reading. He is an assistant clinical professor of medicine at Indiana University School of Medicine in Indianapolis.

So, should you throw away your forearm blood testing device? Absolutely not! Both Alexander and Koschinsky agree that they can be used as long as it's not a potential emergency situation. So, you might want to stick to a finger prick device if you're about to drive a long distance or if you feel you are developing low blood sugar, which is a potentially dangerous condition called hypoglycemia. Alexander also says you might also want to use a finger prick device during the two hours after a meal.

Is This Normal? Get the Facts Fast!

Check Your Blood Sugar Level Now
What type of diabetes do you have?
Your gender:

Get the latest Diabetes newsletter delivered to your inbox!


or
Answer:
Low
0-69
Normal
70-130
High
131+

Your level is currently

If the level is below 70 or you are experiencing symptoms such as shaking, sweating or difficulty thinking, you will need to raise the number immediately. A quick solution is to eat a few pieces of hard candy or 1 tablespoon of sugar or honey. Recheck your numbers again in 15 minutes to see if the number has gone up. If not, repeat the steps above or call your doctor.

People who experience hypoglycemia several times in a week should call their health care provider. It's important to monitor your levels each day so you can make sure your numbers are within the range. If you are pregnant always consult with your health care provider.

Congratulations on taking steps to manage your health.

However, it's important to continue to track your numbers so that you can make lifestyle changes if needed. If you are pregnant always consult with your physician.

Your level is high if this reading was taken before eating. Aim for 70-130 before meals and less than 180 two hours after meals.

Even if your number is high, it's not too late for you to take control of your health and lower your blood sugar.

One of the first steps is to monitor your levels each day. If you are pregnant always consult with your physician.

Did You Know Your Lifestyle Choices
Affect Your Blood Sugar?

Use the Blood Glucose Tracker to monitor
how well you manage your blood sugar over time.

Get Started

This tool is not intended for women who are pregnant.

Start Over

Step:  of 

Today on WebMD

Woman holding cake
Slideshow
feet
Slideshow
 
man organizing pills
Slideshow
Close up of eye
Slideshow
 

Woman serving fast food from window
Video
Can Vinegar Treat Diabetes
Video
 
Middle aged person
Tool
are battery operated toothbrushes really better
Video
 

Prediabetes How to Prevent Type 2 Diabetes
Article
type 2 diabetes
Slideshow
 
food fitness planner
Tool
Are You at Risk for Dupuytrens Contracture
Article