Glucose measurement in body fluids: A ready reckoner for clinicians

Blood glucose measurement is central to the diagnosis and management of patients with diabetes. Considering that a clinician relies heavily on blood (or rarely other body fluid) glucose values for decision making, an understanding of the basic aspects of glucose measurement in body fluids is necessary.

A literature search was conducted in PubMed for articles in English on measurement of glucose in body fluids.

Glucose can be measured in several body fluids, namely blood, interstitial fluid, urine, cerebrospinal fluid, pleural fluid and ascitic fluid in appropriate clinical settings. For blood glucose measurement, the present-day enzymatic methods have replaced the older reducing and condensation methods on account of their better accuracy. It is important to consider preanalytical factors such as sample collection, storage and transport when analyzing a laboratory blood glucose report. The measurement of glucose in interstitial fluid using continuous glucose monitoring system (CGMS) enables better understanding of glucose trends and fluctuations. The CGMS data should be reported using standard metrics which include parameters such as mean 24-h glucose, glycemic variability and time-in, below and above range. The measurement of glucose in urine sample is rarely ever used these days and should be reserved for exceptional circumstances.

This review provides a detailed account of various aspects of glucose measurement including their evolution, pitfalls, and their utility in current clinical practice.