Norm of Dinitrophenylhydrazine (DNpH) Test
Normal amino acid screen.
Usage of Dinitrophenylhydrazine (DNpH) Test
Biotinidase deficiency, cystinuria, Hartnup's homocystinuria disease, maple syrup urine disease, oasthouse urine disease, PKU, tyrosinemia, tyrosinosis, lactic acidosis, fructose-1,6-diphosphatase deficiency, ketosis, seizures, and unexplained mental retardation.
Description of Dinitrophenylhydrazine (DNpH) Test
Metabolic screening test to detect inherited disorders in the metabolism of branched-chain amino acids.
Professional Considerations of Dinitrophenylhydrazine (DNpH) Test
Consent form NOT required.
- Obtain a clean specimen container.
- Obtain a 15-mL random urine specimen.
- Keep the urine sample refrigerated or frozen.
Client and Family Teaching
- Results are normally available within 72 hours.
Factors That Affect Results
- Radiopaque contrast dye may increase the results.
- Falsely elevated results occur if valproic acid, penicillin derivatives, or benzoic acid preservatives have been ingested within 3 days of the urine collection.
- A 24-hour urine sample may also be obtained.
- Peritoneal dialysis may be used to clear amino acids from the body.
- One of the branched-chain amino acids produces a metabolite that causes the urine to smell like maple syrup.
- The test can also be performed on a newborn heelstick blood spot as part of the neonatal screening for metabolic disorders.