methylmalonate in 24 hr urine

Introduction

Metabolism of methylmalonate is dependent upon vitamin B12.

Reference interval

• 24 hour urine: < 9.0 mg/day (< 76 umol/day)
• random urine: < 3.76 mg/g creatinine (< 3.6 mmol/mol creatinine)

Increases

• vitamin B12 deficiency (but NOT folate deficiency)
• renal insufficiency (even mild renal insufficiency)
• chemical interferences with color method
  • acetoacetate
  • ascorbate
  • creatinine
  • uric acid
• congenital methylmalonic aciduria

Methods

• GLC, GC-MS (random urine), color

Specimen

• 24 hour urine
  • administer 10 g of L-valine orally.
  • begin collection of urine immediately after L-valine administration
  • add 10 mL of 6M HCl
  • stable for 3 months when frozen
• random urine:
  • collect 2nd voided specimen after overnight fast
  • store frozen.

More general terms

• 24 hour urine
• methylmalonate in urine

Additional terms

• methylmalonate in serum
• methylmalonate; methylmalonic acid (MMA)