Urine & CSF

VMA (24-h urine) unit converter

Catecholamine breakdown product; screens for pheochromocytoma and neuroblastoma

Also known as: Vanillylmandelic acid

Converter

Enter a value in any unit and all other units fill in.

mg/24 h µmol/24 h

Worked example

3.5 mg/24 h (middle of the reference range) = 17.7 µmol/24 h

Conversion formulas

µmol/24 h	µmol/24 h = mg/24 h × 5.046	mg/24 h = µmol/24 h × 0.1982

Reference range

Unit	Adults
mg/24 h	0 – 7
µmol/24 h	0 – 35.32

Source: University of Iowa Hospitals Pathology Handbook: vanillylmandelic acid · Last reviewed: 2026-10-14

Note from the source: Adults 18 years and older: 0.0-7.0 mg/24 h (Iowa, same as ARUP); limits differ by method (other laboratories use under 6.0 to under 8.0 mg/24 h)

Frequently asked questions

How do I convert VMA (24-h urine) from mg/24 h to µmol/24 h?

µmol/24 h = mg/24 h × 5.046. In the other direction: mg/24 h = µmol/24 h × 0.1982.

What is the reference range of VMA (24-h urine)?

For adults the range is 0 – 7 mg/24 h (University of Iowa Hospitals Pathology Handbook: vanillylmandelic acid). Reference ranges differ between laboratories and partly by sex and age; use the range printed on your lab report.

Which units are used for VMA (24-h urine)?

Common units are mg/24 h, µmol/24 h.