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HelpTest Code HYPOG Hypoglycemic Agent Screen, Serum
Reporting Name
Hypoglycemic Agent Screen, SUseful For
Evaluation of suspected insulinoma characterized by hypoglycemia and increased serum insulin concentration
Detecting drugs that stimulate insulin secretion
Drugs detected by this procedure are:
-The first-generation sulfonylureas: chlorpropamide (Diabinese), tolazamide, and tolbutamide (Orinase)
-The second-generation sulfonylureas: glimepiride (Amaryl), glipizide (Glucotrol), and glyburide (Glibenclamide)
-The meglitinides: repaglinide (Prandin) and nateglinide (Starlix)
-The thiazolidinediones: pioglitazone (Actos) and rosiglitazone (Avandia)
This test is not intended for therapeutic drug monitoring but could be used to monitor compliance.
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedSpecimen Required
Patient Preparation: Specimen must be collected during an episode of hypoglycemia.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume:1.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Frozen (preferred) | 28 days | |
| Refrigerated | 28 days | ||
| Ambient | 7 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
Negative
Screening cutoff concentrations
Chlorpropamide: 100 ng/mL
Glimepiride: 20 ng/mL
Glipizide: 5 ng/mL
Glyburide: 5 ng/mL
Nateglinide: 5 ng/mL
Pioglitazone: 20 ng/mL
Repaglinide: 5 ng/mL
Rosiglitazone: 20 ng/mL
Tolazamide: 50 ng/mL
Tolbutamide: 20 ng/mL
Note: If a drug is detected at a concentration greater than the cutoff, the report will indicate that specific drug is positive. The test cutoff listed for each drug is lower than the concentration that will cause increased insulin and decreased glucose.
Day(s) Performed
Monday, Wednesday, Friday
CPT Code Information
80377
G0480-(if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HYPOG | Hypoglycemic Agent Screen, S | 68318-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 21295 | Chlorpropamide | 48329-7 |
| 21298 | Glimepiride | 48325-5 |
| 21299 | Glipizide | 48326-3 |
| 21300 | Glyburide | 48327-1 |
| 609767 | Nateglinide | 49487-2 |
| 609768 | Pioglitazone | 100351-6 |
| 21301 | Repaglinide | 48328-9 |
| 609769 | Rosiglitazone | 100352-4 |
| 21296 | Tolazamide | 21566-5 |
| 21297 | Tolbutamide | 21567-3 |
Clinical Information
The metabolic and hormonal profiles of insulinoma and sulfonylurea-induced hypoglycemia are identical. Therefore, in the evaluation of the hypoglycemic patient, the possible use of oral hypoglycemic agents as the cause for low blood glucose and elevated serum insulin must be considered. Absence of hypoglycemic drugs in serum during an episode of low blood glucose should be demonstrated before considering pancreatic exploration for suspected insulinoma.
Interpretation
Use of hypoglycemic agents outside of the context of treatment of type 2 diabetes is likely to cause hypoglycemia associated with elevated serum insulin. Patients presenting with hypoglycemia due to ingestion of a first-, second-, or third-generation hypoglycemic agents will have drug present in serum greater than the minimum effective concentration (see Reference Values). Presence of drug indicates that the patient has recently ingested a hypoglycemic agent.
Cautions
Proper interpretation requires that the specimen be collected during or close to the time of a hypoglycemic episode. Drugs will not be detected (and are not likely to be present) if blood is drawn when blood glucose is normal in nondiabetic patients.
All drugs that stimulate insulin secretion undergo extensive metabolism before excretion. The parent drug is therefore not present in urine. Blood serum is the specimen of choice for detecting use of the hypoglycemic drugs; urine or plasma is not an acceptable specimen.
This screen does not include the first-generation sulfonylurea acetohexamide.
Other drugs that do not induce hypoglycemia, thiazolidinediones such as troglitazone and lobeglitazone, and are designed to make tissues more sensitive to insulin are not included in this screen test.
Drugs that lower blood glucose through mechanisms not related to stimulation of insulin secretion, such as acarbose, metformin, and miglitol, are not included in this screen test.
Method Description
Serum specimens are subjected to organic extraction. The extract is analyzed by liquid chromatography tandem mass spectrometry.(Unpublished Mayo method)