Posted Date
Effective Date
Test Name
N-Methylhistamine, 24 Hour Urine
Update Type
Reference range changed
CPT Code
82542
Order Code
NMH24
REFERENCE RANGE CHANGE
N-Methyl Histamine, 24 Hour Urine
Order Code: NMH24
Fee Code: AA223 (CPT 82542)
LOINC: 44340-8
Reference Laboratory: Mayo NMH24
Please note that there will be a change to the reference range for the N-Methyl Histamine, 24 Hour Urine assay effective September 14, 2026:
Reference Range:
N-METHYLHISTAMINE
0-5 years: 85-369 mcg/g creatinine
6-16 years: 48-238 mcg/g creatinine
>16 years: 19-143 mcg/g creatinine
CREATININE
Males: 930-2955 mg/24 hours
Females: 603-1783 mg/24 hours
Reference values have not been established for patients who are younger than 18 years.