Aug. 4, 2008 -- There are many products to choose from to check your blood pressure or blood glucose at home, but they vary in accuracy, an investigation by Consumer Reports finds.
The results of the investigation appear in the September issue of the magazine.
"The main message is that not all blood pressure and blood glucose monitors are alike in terms of accuracy and ease of use," Consumers Union Chief Medical Advisor Marvin M. Lipman, MD, tells WebMD. Consumers Union is a nonprofit organization that publishes Consumer Reports.
None of the tested monitors received a "not recommended" rating, but several were rated fair or poor in terms of accuracy.
Among the major findings from the investigation:
- Automatic upper-arm cuff blood pressure monitors tended to give better readings than wrist monitors.
- Price was not a good predictor of accuracy with blood glucose meters. Two of the cheapest models tested were among the four highest scorers.
- The only combined blood pressure/blood glucose monitor tested scored poorly, ranking 16th out of 16 in the accuracy of blood pressure readings.
- A blood pressure monitor and a blood glucose monitor sold at Wal-Mart were amongst the best performing and least expensive models tested.
Blood Pressure Monitors
Seventy-three million Americans have high blood pressure, and for an estimated 65% of them, the condition is poorly controlled.
American Heart Association spokesman David A. Meyerson, MD, who is director of cardiology consultative services at John's Hopkins Bayview Medical Center, says the accuracy of the new generation of home blood pressure monitors prompted the recommendation.
"Doctors used to feel that the blood pressure readings they got in their offices were the only ones they could rely on, but that has changed," he tells WebMD. "Home testing is now an important part of monitoring. When a patient brings in twice-daily readings for a month I have a much more accurate record of their blood pressure control than I would get with office readings taken three or four times a year."
In earlier tests by Consumers Union, finger-type blood pressure monitors performed so poorly that they were not even included in the current analysis, Lipman says. "The finger monitors are vastly inferior and the wrist monitors don't work as well as the arm. It seems that the closer you get to the heart, the better off you are."
The American Heart Association also recommends automatic upper-arm cuff monitors, but not the wrist or finger devices.
"The accuracy and variability of the readings we have seen with finger and wrist monitors are so wide that we can't recommend them," Meyerson says.
Of the 16 monitors tested, the top four were all upper-arm cuff devices and all were judged excellent for accuracy.
- Omron's Women's Advanced Elite 7300W ($100)
- CVS by Microlife Delux Advanced 344534 ($90)
- Omron's HEM-711AC ($90)
- ReliOn HEM-741CREL from Wal-Mart ($40)
The Duo-Care combined blood glucose and wrist blood pressure monitor was the poorest performing blood-pressure monitor tested, receiving the only poor rating for accuracy.
Blood Glucose Monitors
None of the 13 tested blood-glucose monitors performed poorly in terms of consistency and accuracy, but Consumer Reports Health Editor Gayle Williams says she was surprised to find that one of the top performers was also one of the cheapest.
The ReliOn Ultima (ranked fourth), sold at Wal-Mart, cost just $9, with test strips averaging just 44 cents each. Strips for three other top performers averaged just over $1 a piece.
"Someone might see a $9 glucose meter and say it can't possibly work when most other meters cost $70 or $80, but it performed very well," she says. "And a strip that costs 44 cents is going to save someone who tests three or four times a day a lot of money."
Among the other top performers:
- The OneTouch UltraMini ($20, $1.14 per strip)
- Ascensia Contour ($80, $1.10 per strip)
- OneTouch Ultra2 ($70, $1.14 per strip)
- Accu-Chek Compact Plus ($73, $1.10 per strip)
- OneTouch UltraSmart ($85, $1.14 per strip)
While it was rated very good in terms of accuracy, the Duo-Care combined blood glucose and wrist device scored poorly in terms of ease of use.
The investigators found that the Duo-Care device could accidentally be set to show sugar levels in foreign measurement units, rather than in U.S. units.
A spokesman for the company that manufactures the Duo-Care tells WebMD that the product is preset for use in the U.S., and the instructions for changing to a different measurement unit are clear.
Genexel-Sein Vice President Douglas Stafford says the Duo-Care dual device underwent rigorous testing for accuracy in order to meet FDA standards for sale in the U.S.
"Every product [Consumer Reports] tested meets FDA requirements for accuracy, and FDA holds everyone to the same high standards," he says.
The Duo-Care device is among the only combined blood glucose and blood pressure monitors sold in the U.S.; Stafford says the response from the diabetes community has been very positive.
"We talk to a lot of physicians, nurses, and other diabetes educators who tell us they have been waiting for something like this because blood pressure control is critical for diabetics," he says.
"Many of the serious side effects of diabetes are the result of poor blood pressure control, and this product reminds patients that monitoring blood pressure is important just like monitoring blood glucose."