Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (651 page)

   Limitations

   A large number of substances may interfere with this test.

   Decreases may be caused by carbamazepine, cephaloridine, cephalothin, chlormerodrin, digoxin, glucose, metyrapone, promazine, propoxyphene, reserpine, and others.

   Increases may be caused by acetone, acetophenide, ascorbic acid, chloramphenicol, chlorothiazide, chlorpromazine, cloxacillin, dexamethasone, erythromycin, ethinamate, etryptamine, methicillin, methyprylon, morphine, oleandomycin, oxacillin, penicillin, phenaglycodol, phenazopyridine, phenothiazine, piperidine, quinidine, secobarbital, spironolactone, and others.

5,10-METHYLENETETRAHYDROFOLATE REDUCTASE (MTHFR) MOLECULAR ASSAY
*

   Definition

   Mutations, C677T and A1298C, in the 5,10-methylenetetrahydrofolate reductase (
MTHFR
) gene increase the risk of thrombosis (OMIM# 188050) and other cardiovascular disorders as a result of an elevated plasma homocysteine concentration (OMIM# 236250).

   
Normal values:
negative or no mutations are found.

   Use

   Suspected coronary artery disease, homocystinuria, neural tube defects, spontaneous abortion, or MTHFR deficiency

   Limitations

   The results of a genetic test may be affected by DNA rearrangements, blood transfusion, bone marrow transplantation, or rare sequence variations.

5-HYDROXYINDOLEACETIC ACID (5-HIAA) URINE

   Definition

   5-Hydroxyindoleacetic acid (5-HIAA), also known as serotonin metabolite, is the major urinary metabolite of serotonin.