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VMA is found in the urine, along with other catecholamine metabolites, including homovanillic acid (HVA), metanephrine, and normetanephrine. In timed urine tests the quantity excreted (usually per 24 hours) is assessed along with creatinine clearance, and the quantity of cortisols, catecholamines, and metanephrines excreted is also measured.
5-HIAA is tested by 24-hour urine samples [1] combined with an acidic additive to maintain pH below 3. Certain foods like pineapple, kiwi, banana, walnuts and drugs such as acetaminophen, nicotine or caffeine are known to interfere with the measurement.
Elevated plasma free metanephrines is considered the gold standard diagnosis for pheochromocytoma. [63] Over 10 studies have confirmed that the sensitivity and specificity of this test is 97% and 93% respectively; however, there is still concern for false positive results in the correct clinical scenario. [6]
Abnormal kidney function may cause too much or too little urine to be produced. The ability of the kidneys to filter protein is often measured, as urine albumin or urine protein levels, [2] measured either at a single instance or, because of variation throughout the day, as 24-hour urine tests. [citation needed]
Normetanephrine, also called normetadrenaline, [1] is a metabolite of norepinephrine created by action of catechol-O-methyl transferase on norepinephrine. It is excreted in the urine and found in certain tissues.
Elevated urinary orotic acid levels can also arise secondary to blockage of the urea cycle, particularly in ornithine transcarbamylase deficiency (OTC deficiency). This can be distinguished from hereditary orotic aciduria by assessing blood ammonia levels and blood urea nitrogen (BUN).
Hypertryptophanemia is a rare autosomal recessive [2] metabolic disorder that results in a massive buildup of the amino acid tryptophan in the blood, with associated symptoms and tryptophanuria (-uria denotes 'in the urine'). [3] [4] Elevated levels of tryptophan are also seen in Hartnup disease, [5] a disorder of amino acid transport. [6]
Polydipsia and polyuria occur when blood glucose levels rise high enough to result in excretion of excess glucose via the kidneys, which leads to the presence of glucose in the urine. This produces an osmotic diuresis. [citation needed] Signs and symptoms of diabetic ketoacidosis may include: [citation needed] Ketoacidosis