Sorted By Test Name - Mayo Medical Laboratories

INHP
9768
IVD
83644
6 > or =100 Strongly positive Reference values
apply to all ages.
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by
Laboratory Methods. 21st edition. Edited by RA McPherson, MR Pincus. New York, WB Saunders
Company, 2007, Chapter 53, Part VI, pp 961-971
Isoniazid, Serum/Plasma
Reference Values:
Reporting limit determined each analysis
Synonym(s): INH
Usual therapeutic range in the treatment of tuberculosis:
1-7 mcg/mL. Toxic symptoms present at approximately
20 mcg/mL and greater.
Test Performed by: NMS Labs
3701 Welsh Road
PO Box 433A
Willow Grove, PA 19090-0437
Isovaleryl-CoA Dehydrogenase (IVD) Mutation Analysis (A282V)
Clinical Information: Isovaleric acidemia (IVA) is an autosomal recessive inborn error of leucine
metabolism associated with germline mutations of the isovaleryl-CoA dehydrogenase gene. Mutations in
this gene cause isovaleryl-CoA dehydrogenase (IVD) deficiency. This enzyme defect results in the
accumulation of derivatives of isovaleryl-CoA, including free isovaleric acid, 3-OH valeric acid,
N-isovalerylglycine, and isovalerylcarnitine. Diagnosis relies primarily on the identification of these
metabolites in urine by organic acid and acylglycine analyses, and in plasma by acylcarnitine analysis.
Patients with IVA may present with various phenotypes, from the acute, neonatal phenotype to the
chronic intermittent phenotype. Typically patients present with fairly non-specific features including poor
feeding and vomiting. During these episodes, a characteristic smell of "dirty socks" may be present. In the
past, many patients with neonatal onset died during the first episode, while survivors of acute
manifestations often suffered neurological sequelae due to incurred central nervous system damage.
Therefore, early diagnosis and treatment is of the utmost importance. Newborn screening for IVA was
established to allow for early detection by acylcarnitine analysis and presymptomatic initiation of
treatment. This early detection has led to improved prognosis for IVA patients. Molecular follow up
testing for patient's with positive newborn screening for IVA has led to the identification of specific
mutant alleles. One such mutant allele, A282V, has been found to be over represented in patients detected
by newborn screening. Clinical evaluation of patients with the A282V mutant allele suggests that this
specific mutant allele may confer a milder clinical phenotype. Accordingly, determination of the patient's
genotype with respect to the A282V mutation has implications for patient management and genetic
counseling.
Useful For: Confirmation of clinical and/or biochemical diagnosis of isovaleric acidemia Providing
prognostic information
Interpretation: An interpretive report will be provided.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Ensenauer R, Vockley J, Grunert S, et al: A common mutation is associated
with a mild, potentially asymptomatic phenotype in patients with isovaleric academia diagnosed by
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