: Glucose [Mass concentration] in Serum or Plasma

: What This Test Measures

: Glucose is your body's main source of energy, and its level in the blood is tightly controlled. This test quantifies the mass concentration of glucose in serum or plasma, typically reported in milligrams per deciliter (mg/dL). The specimen is processed from a blood draw, and the liquid portion is analyzed.

: Why It Is Ordered

: Healthcare providers order blood glucose testing to screen for diabetes or prediabetes, to monitor people already diagnosed with diabetes, and to investigate symptoms such as excessive thirst, frequent urination, fatigue, or confusion. It may also be part of a routine metabolic panel or emergency evaluation.

: How to Prepare

: Preparation depends on which type of test your provider ordered. A fasting glucose requires you to avoid food and most drinks for a set period before the draw, while a random glucose does not. Follow the specific instructions you are given, and tell the staff about any medications you take.

: What Results Mean

: Results are interpreted against the reference range established by the performing laboratory, which can vary between labs. A value outside the range does not by itself diagnose a condition; providers consider your symptoms, history, and other tests. Very low or very high values may require prompt medical attention.