Urine Analysis: Part 24 – VMA (Vanillylmandelic acid), Catecholamines (24 hours urine), Neuroblastoma
- The test is done in the urine.
- Collect 24 hours urine sample.
- Discard the first urine sample and not the time. Now collect all urine samples in the container containing 6 mL of HCl. Collect the last sample when 24 hours are completed.
- Or add 20 mL of HCL (6 mol/L)
- Refrigerate the urine during collection and is stable for 2 weeks.
- The sample is stable for 2 weeks at 2 to 4 °C.
- Following foods and drugs cause the false raised level of VMA.
- Avoid chocolate, coffee, tea, and cocoa for 2 to 3 days before the test is performed.
- Avoid food like citrus fruits, bananas, and food with vanilla.
- Avoid beer and red wine.
- Avoid drugs like aspirin and antihypertensive medicines.
- Vigorous exercise and stress may increase the VMA level.
- Decreased VMA levels may be seen in patients with uremia, alkaline urine, and radiographic contrast media.
- Drugs that may increase the level are levodopa, lithium, nitroglycerine, epinephrine, and caffeine.
- Drugs that may decrease the level are phenothiazine, reserpine, guanethidine, monoamine oxidase inhibitor, and disulfiram.
Purpose of the test (Indications)
- To diagnose pheochromocytoma.
- For Tumors of the adrenal medulla.
- To detect neuroblastoma.
- In patients with hypertension.
- The catecholamines are formed from the precursor Tyrosine with the action of different enzymes.
- The Adrenal Gland makes a lot of catecholamines as a reaction to stress.
- The end product of catecholamines is VMA excreted in the urine.
- 3-methoxy-4-hydroxymandelic acid is also called VMA.
- The main catecholamines are:
- Norepinephrine (Noradrenaline).
- catecholamines break down into VMA + Metanephrine, which is excreted in the urine.
- VMA has 10 to 100 times more concentration in the urine than other amines.
- Increased catecholamine is found in the patient with:
- Fall in blood pressure (Decreased blood volume).
- Thyroid hormone deficiency.
- Congestive heart failure.
- Decreased level of catecholamines seen in a patient with idiopathic postural hypotension.
- Signs and symptoms:
- Most common tumors of children under the age of 5 years.
- It arises anywhere along with the sympathetic nervous system.
- A common site is the adrenal medulla.
- Due to increased catecholamines from the adrenal medulla, there are:
- Rapid heartbeat.
- Before the tumor is diagnosed, there is already spread to lymph nodes, liver, lungs, bone, and bone marrow.
- Diagnosed by:
- Biopsy with immunocytochemistry.
- Bone marrow for the presence of cancer cells.
- Increased blood or urine level of catecholamines metabolites like:
- HVA (homovanilic acid).
- Urinary measurement is preferred.
- Radiology like CT or MRI.
- Bone marrow transplantation.
|0 to 10 day||<1.0|
|10 days to 24 months||<2.0|
|24 months to 18 years||<5.0|
|Adult||2.1 to 7.6|
- Adult/elderly = <6.8 mg/24 hours
- Adolescent = 1 to 5 mg/24 hours
- Child = 1 to 3 mg/24 hours
- Infants = <2 mg/24 hours
- Newborn = <1 mg/24 hours
|VMA||up to 9 mg/24 hours|
|VMA Some reference says||2.1 to 7.6 mg/24 hours|
|Catecholamines total||<100 µg/ 24 hours|
|Epinephrine||0 to 20 µg/ 24 hours||<50 pg/mL|
|Metanephrine||74 to 297 µg/ 24 hours|
|Norepinephrine||15 to 80 µg/ 24 hours||110 to 410 pg/mL|
|Dopamine||65 to 400 µg/ 24 hours||<87 pg/mL|
Increased VMA level is seen in:
- Adrenal glands tumor (Pheochromocytoma)
- It May be seen in any major stress like:
- Body infections ( sepsis).
- Surgery or traumatic injury.
- Many blood pressure drugs.
- Carcinoid tumors.
Decreased VMA level is seen in:
- In Diabetes
Increased Catecholamine is seen in:
- Diabetic acidosis.
- Myocardial infarction.
Decreased Catecholamine is seen in:
- Diabetic neuropathy.
Normal urine picture:
Physical features Chemical features Microscopic findings
- Color = Pale yellow or amber
- Appearance = Clear to slightly hazy
- pH = 4.5 to 8.0
- Specific gravity = 1.015 to 1.025
- Blood = Negative
- Glucose = Negative
- Ketones= Negative
- Protein = Negative
- Bilirubin = Negative
- Urobilinogen = Negative (±)
- Leucocyte esterase = Negative
- Nitrite for bacteria = Negative
- RBCs = Rare or Negative
- WBC = Rare or Negative
- Epithelial cells = Few
- Cast = Negative (Occasional hyaline)
- Crystal = Negative (Depends upon the pH of the urine)
- Bacteria = Negative