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Company
Urinalysis
Review status
Currently under review
Pending specialist review and validation.
Urine Arginine measures the amount of arginine, an essential amino acid, excreted in your urine. Laboratories often report it relative to creatinine to account for how concentrated or dilute the urine is.
The test is commonly performed as part of a urine amino acids profile to evaluate how your body processes proteins and to help screen for certain inherited metabolic conditions.
Changes in urinary arginine can point to issues with the urea cycle, liver function, kidney tubular handling, or nutritional status. Your clinician may order this test after an abnormal newborn screen, when symptoms suggest a metabolic disorder, or to monitor a known condition or treatment plan.
It can also provide clues when there are unexplained growth or developmental concerns, neurologic symptoms, or when you use specialized diets or amino acid supplements.
Results are interpreted using age specific reference intervals and by comparing arginine with other amino acids in urine and blood. A higher result may prompt confirmatory testing such as plasma amino acids, ammonia, liver tests, and genetic evaluation, while a lower result can reflect diet, dilution from high fluid intake, or kidney handling.
Because the value is adjusted to creatinine, changes in muscle mass or kidney function can affect the ratio. If results are unexpected, your clinician may suggest repeating a first morning sample, reviewing diet and medications, and coordinating follow up with a metabolic specialist when needed.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Drinking a large amount of fluid before collection can dilute the specimen, while dehydration can concentrate it. A first morning sample often gives a steadier picture, although the creatinine ratio helps correct for concentration.
High protein meals, arginine containing sports supplements, or protein shakes can raise urinary arginine. Fasting, poor intake, or malnutrition can lower it. Tell your clinician about any dietary products you use.
Intravenous arginine, nitric oxide donor products, corticosteroids, and some diuretics can influence amino acid excretion or urine concentration. Do not start or stop medicines or supplements without medical guidance.
Fever, infection, trauma, or strenuous exercise can shift protein metabolism and transiently alter results. When possible, routine monitoring is best performed when you are well and activity is typical.
Kidney tubular disorders, reduced kidney function, or liver disease can change arginine handling and affect the creatinine ratio. In urea cycle disorders such as arginase deficiency, values may be persistently higher and need specialist follow up.
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