A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Glucose Tolerance, 4 Specimens
Test Code10559
CPT Codes
82951, 82952
Preferred Specimen
1 mL plasma collected in each of four separate fluoride/oxalate (gray-top) tubes
Patient Preparation
Fasting required. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before testing.
Minimum Volume
0.5 mL for each specimen
Other Acceptable Specimens
Plasma collected in each of four separate fluoride/oxalate (gray-top) tubes in a plastic screw-cap vial • Serum (separated from cells immediately) collected in each of four separate plastic screw-cap vials • Spun serum collected in each of four separate serum separator tubes • Plasma collected in each of four separate lithium heparin (green-top) tubes in a plastic screw-cap vial • Plasma collected in each of four separate sodium heparin (green-top) tubes in a plastic screw-cap vial • Whole blood collected in each of four fluoride/oxalate (gray-top) tubes
Instructions
Immediately after a fasting specimen is obtained, have patient ingest a 75 g loaded dose of glucose. Draw subsequent specimens per physician's order. If not specified by the physician, draw specimens 1, 2 and 3 hours later. Label each with the specific draw time.
Note: Serum and plasma submissions must be separated from cells.
Note: Serum and plasma submissions must be separated from cells.
Transport Temperature
Sodium fluoride plasma (preferred) and serum: Room temperature
Heparinized Plasma and whole blood: Refrigerated
Heparinized Plasma and whole blood: Refrigerated
Specimen Stability
Sodium fluoride Plasma (preferred)
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Whole blood
Room temperature: 24 hours
Refrigerated: 72 hours
Frozen: Unacceptable
Serum
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days
Heparinized plasma
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 28 days
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Whole blood
Room temperature: 24 hours
Refrigerated: 72 hours
Frozen: Unacceptable
Serum
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days
Heparinized plasma
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Unspun SST, red-top or non-plasma separator (PST) green-top tubes • Anticoagulants other than lithium heparin, sodium heparin or fluoride/oxalate
Methodology
Spectrophotometry (SP)
Setup Schedule
Set up: Daily; Report available: Next day
Reference Range
American Diabetes Association Diagnostic Criteria for Diabetes Mellitus |
|||||||
Glucose Value (mg/dL) | |||||||
Interpretation | Fasting | 1 Hr Tolerance | 2 Hr Tolerance | ||||
Normal | <100 | Not established | <140 | ||||
Impaired Fasting | 100-125 | ||||||
Impaired Tolerance | 140-199 | ||||||
Diabetes | ≥126* | ≥200* |
Specimen 1: 65-99 mg/dL
Clinical Significance
For appropriate interpretation of this test, the patient must fast overnight and ingest a 75 g load of glucose, immediately after a fasting specimen is obtained. (for children, the glucose load is 1.75 g/kg of body weight, up to 75). The diagnosis of diabetes is made if glucose exceeds 200 mg/dL in the 2 hour specimen and in any preceding specimen.
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153