Question

What is VMA? And what is the significance of it? What is the best sample to evaluate it & WHY?  

Answer 1

VMA (vanilymandelic Acid ) is one of the breakdown products (metabolities) of epinephrine (adrenaline) and nor epinephrine.Epinephrine and nor epinephrine belong to a group of similar hormones called catecholamines.The primary catecholamines are dopamine ,epinephrine and nor epinephrine.

SIGNIFICANTES OF VMA;

VMA (vanilymandelic Acid ) test is primarily used to detect and rule out tumors called neuroblastomas mass in children with an abnormal mass or other symptoms suggestive of the disease.

Abnormalities of catecholamine production-

*Pheochromocytomas ;these are the tumors of adrenal medulla .The diagnosis of pheochromocytomas is possible only when their is an excessive production of epinephrine ans nor epinephrine that causes severe hypertension.

*The individual affected by this disorder the ration of nor epinephrine to epinephrine is increased.

urinary VMA -( normal< 8mg/day) is helpfull in the diagnosis of pheochromocytomas.

BEST SAMPLE TO EVALUATE VMA;

The VMA test ,along with other tests for catecholamines and their metabolities,can be used to help detect the presence of neuroblastomas.The preffered tests for pheochromocytomas are plasma free metanephrine ,urine metanephrines,and urine or plasma catecholamine test.

URINE is the best sample .Because the metabolic products metanephrine and vanilymandelic acid ( VMA) are excreted in urine.