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Test Code C5OHU C5-OH Acylcarnitine, Quantitative, Random, Urine

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

C5-OH Acylcarnitine, QN, U

Specimen Type

Urine


Ordering Guidance


This second-tier test is used specifically to evaluate a newborn screening elevation of 3-hydroxyisovaleryl-/2-methyl-3-hydroxy acylcarnitine and must not be ordered with either C4U / C4 Acylcarnitine, Quantitative, Random, Urine or C5DCU / C5-DC Acylcarnitine, Quantitative, Random, Urine.

 

For general screening for metabolic disorders, see OAU / Organic Acids Screen, Random, Urine; ACRN / Acylcarnitines, Quantitative, Plasma; and AAQP / Amino Acids, Quantitative, Plasma.



Necessary Information


Include patient's age, family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.

Specimen Required


Patient Preparation: If clinically feasible, discontinue L-carnitine supplementation at least 72 hours before specimen collection.

Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a random urine specimen.

2. Freeze specimen immediately.


Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 7 days
  Refrigerated  24 hours

Specimen Minimum Volume

1 mL

Day(s) Performed

Monday, Wednesday, Friday

Specimen Retention Time

1 month

Report Available

2 to 5 days

Reference Values

<2.93 millimoles/mole creatinine

Useful For

Evaluation of patients with an abnormal newborn screen showing elevations of 3-hydroxyisovaleryl-/2-methyl-3-hydroxybutyryl-carnitine

CPT Code Information

82017

LOINC Code Information

Test ID Test Order Name Order LOINC Value
C5OHU C5-OH Acylcarnitine, QN, U 50091-8

 

Result ID Test Result Name Result LOINC Value
88830 C5-OH Acylcarnitine, QN, U 50091-8
28125 C5-OH Interpretation 59462-2
34469 Reviewed By 18771-6

Genetics Test Information

Elevated 3-hydroxyisovaleryl-/2-methyl-3-hydroxy acylcarnitine (C5-OH) in plasma or newborn screening blood spots is due to one of several biochemical genetic diagnoses: 3-methylcrotonylglycinuria, 3-hydroxy 3-methylglutaryl-CoA lyase deficiency, beta-ketothiolase deficiency, 2-methyl 3-hydroxybutyryl-CoA dehydrogenase deficiency, 3-methylglutaconic aciduria, biotinidase deficiency or holocarboxylase deficiency.

 

Urine C5OH is useful in differentiating patients with 3-methylcrotonylglycinuria and with 3-methylglutaconic aciduria as they typically excrete larger amounts of C5-OH in urine compared to patients with the other diagnoses.