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U.S. Department of Health and Human Services

Medical Devices

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Common Problems with the Use of Glucose Meters at the Point of Care

Glucose Testing Tips:

Diabetes care has come a long way since the introduction of insulin and the first oral anti-hyperglycemic medicines. Life span and quality of life have improved for the majority of affected individuals. Even better, a large part of diabetic care formerly performed in hospital clinics can now be managed at home with use of well-designed home based glucose meters, a telephone and a good patient-doctor relationship.

The Office of In Vitro Diagnostics and Radiological Health (OIR) is charged with the job of evaluating many devices, including glucose meters. OIR helps bring these meters to the public market. Another of OIR’s tasks is the continuous evaluation of these devices for long term safety and effectiveness as well as monitoring how the devices are used.

OIR is taking this opportunity to provide some friendly tips for health care providers. These tips were inspired by comments we have received from manufacturers and users of these devices in point-of-care glucose testing, where testing is done at or near the site of patient care.

False results may be due to problems with the sample or device, or due to user error. Some common problems and their effects on meter glucose readings are listed below.

ProblemResultsRecommendation
Test strip not fully inserted into meterfalse lowalways be sure test strip is fully inserted in meter
Patient sample site (for example, the fingertip) is contaminated with sugarfalse highalways clean and dry test site before sampling
Not enough blood applied to stripfalse lowrepeat test with a new sample
Batteries low on powererror codeschange batteries and repeat sample collection
Test strips/Control solutions stored at temperature extremesfalse high/lowstore kit and components according to directions
Patient is dehydratedfalse highstat venous sample on main lab analyzer
Patient in shockfalse lowstat venous sample on main lab analyzer
Squeezing fingertip too hard because blood is not flowingfalse lowrepeat test with a new sample from a new stick
Sites other than fingertipshigh/lowresults from alternative sites may not match finger stick results
Test strip/Control solution vial crackedfalse high/lowalways inspect package for cracks, leaks, etc.
Anemia/decrease hematocritfalse highvenous sample on main lab analyzer
Polycythemia/increased hematocritfalse lowvenous sample on main lab analyzer

The advantage of point-of-care testing is eliminated if proper technique is not followed. In addition to the above recommendations, laboratory professionals must remember to wash hands and change gloves between patients.

To protect both patients and health care workers from the risk of transmission of bloodborne pathogens such as viral hepatitis B, the entire external surface of the meter should always be cleaned and disinfected between patients. The device manufacturer’s instructions should be followed for cleaning and disinfection procedures. Lancing devices should never be used on multiple patients. Only single-use, disposable lancing devices should be used with multiple-patient use meters.

All operators, from patients to non-lab health care workers to medical technologists and physicians, should be thoroughly familiar with any device prior to using it. The best way to do this is to read the package insert and user manual carefully before using a device for the first time.

It sounds simple, and it is.

If you have any questions, ask someone who is familiar with the device. Another option is calling the customer service telephone number located on most package inserts. The people on the other end are there to help. Another good tip is to reread the package insert every few months. It is a good practice and there may be changes.

Next, watch an experienced laboratory professional, doctor, nurse or diabetic educator perform the test. Then perform the test in front of someone who has experience in using the glucose meter and instructing others on its performance. Ask for tips.

Specific problems come up from time to time including glucose readings that don’t make sense. For example, the patient might feel fine when the glucose meter reading is obviously too high or too low. Remember, the best way to resolve any questionable result, and the best sample from any sick patient, is still a venous blood sample tested at a central lab. Even then any result that does not fit the clinical picture needs to be investigated and, at a minimum, repeated.