Glucometers

Glucometers are handheld medical devices used to measure the concentration of glucose in capillary blood samples, primarily by people with diabetes to monitor glycemic control. They are designed to provide a rapid numerical reading that can be recorded for trend analysis or treatment decisions. Glucometers typically use a disposable test strip that contains enzymes such as glucose oxidase or glucose dehydrogenase.

During testing, a small drop of blood is applied to the strip, where the enzyme catalyzes a reaction with glucose. In most newer meters, the reaction generates an electrical current measured by the meter (electrochemical detection); older or optical meters may detect a color change. The resulting signal is translated into a glucose concentration, reported in mg/dL or mmol/L depending on locale and meter settings.

Most meters are comprised of a digital display, a memory for recent readings, and sometimes wireless capabilities. They are used with a lancing device to obtain a finger-prick sample, though some models allow testing from alternative sites. Calibration is often automatic, but some meters require periodic calibration with control solutions, and others rely on test strip batch calibration.

Accuracy is governed by international standards, such as ISO 15197, and by manufacturer specifications. Factors affecting accuracy include sample hematocrit, temperature, and insufficient blood on the strip. Readings should be interpreted in context and, when in doubt, confirmed with laboratory testing or clinical advice.

Relation to CGMs: Continuous glucose monitors measure interstitial glucose continuously and provide trends; they complement glucometers but are distinct devices.