Synonyms

   Random blood glucose

Clinical Significance

   It is useful for diagnosing and managing diabetes mellitus and other carbohydrate metabolism disorders including gestational diabetes, neonatal hypoglycemia, idiopathic hypoglycemia, and pancreatic islet cell carcinoma.

Specimen

   Serum

Stability

   Refrigerated (preferred) : 7 days

   Frozen : 30 days

Reference Range

   75.6- 180 mg/dL

Interpretation

   Any of the following results, confirmed on a subsequent day, can be considered diagnostic for diabetes: Fasting plasma or serum glucose ≥ 126 mg/dL after an 8-hour fast, 2-Hour plasma or serum glucose ≥ 200 mg/ dL during a 75-gram oral glucose tolerance test (OGTT), Random glucose >200 mg/dL, plus typical symptoms.

   Patients with "impaired" glucose regulation are those whose fasting serum or plasma glucose fall between 101 and 126 mg/dL, or whose 2-hour value on oral glucose tolerance test fall between 140 and 199 mg/dL. These patients have a markedly increased risk of developing type 2 diabetes and should be counseled for lifestyle changes and followed up with more testing. Indications for screening and testing include strong family history, marked obesity, history of babies over 9 pounds, and recurrent skin and genitourinary infections.

   Glucose levels of 25 mg/dL or lower in infants younger than 1 week are considered to be potentially life threatening, as are glucose levels of 40 mg/dL or lower in infants older than 1 week. Glucose levels of 400 mg/dL and higher are considered a critical value.

Limitation

   At ambient temperature, the glucose concentration in the blood will decrease by 10% per hour. Therefore, in a nongel separator tube, the specimen should be centrifuged as soon as possible and the plasma or serum removed from the cells. If the blood is drawn in a serum separator tube (SST) or plasma separator tube (PST), the glucose is stable once the specimen has been spun and the gel is in place.