Diagnosing and managing diabetes mellitus
Enzymatic Photometric Assay
Sugar, Blood
Sugar, Plasma
Serum
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
0.25 mL
Gross hemolysis | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 7 days | |
Frozen | 30 days |
Diagnosing and managing diabetes mellitus
The most common disease related to carbohydrate metabolism is
Overproduction or excess administration of insulin causes a decrease in blood glucose to levels below normal. In severe cases, the resulting extreme hypoglycemia is followed by muscular spasm and loss of consciousness, known as insulin shock.
0-11 months: not established
> or =1 year: 70-140 mg/dL
Any of the following results, confirmed on a subsequent day, can be considered diagnostic for diabetes:
-Fasting plasma or serum glucose > or =126 mg/dL after an 8-hour fast
-2-Hour plasma or serum glucose > or =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.
Once the blood is drawn, the cells in the blood begin to metabolize the glucose that is present in the specimen. 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.
Inhibitors of glucose metabolism such as fluoride also can be used. In these tubes, glycolysis will take place, but at a much reduced rate (approximately 10% over 3 hours).
Chapter 25: In Tietz Textbook of Clinical Chemistry. Fourth edition. Edited by CA Burtis, ER Ashwood, DE Bruns. WB Saunders Company, Philadelphia, 2006, pp 837-907
Glucose in the serum, in the presence of hexokinase, is converted
Monday through Sunday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
82947
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
GLURA | Glucose, Random, S | 2345-7 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
GLURA | Glucose, Random, S | 2345-7 |