Platform
Company
Urinalysis
Review status
Currently under review
Pending specialist review and validation.
Urine Histidine measures the amount of the amino acid histidine that your kidneys excrete into urine. Laboratories typically normalize the result to creatinine to account for how dilute or concentrated the urine is. The test can be ordered on its own or as part of a broader urine amino acids evaluation.
Histidine is important for growth, tissue repair, and many metabolic pathways. Measuring it in urine helps clinicians look for patterns of amino acid handling by the kidneys and for inherited or acquired conditions that affect amino acid metabolism.
Your clinician may order this test when there is concern for an inborn error of metabolism, when a child has developmental concerns or unexplained findings on newborn screening, or when kidney tubular function problems are suspected. It can also be used with other tests to assess nutritional status or to monitor specialized feeding, such as parenteral nutrition.
Higher or lower urinary histidine can be seen for many reasons. Elevated values may occur with certain genetic conditions, generalized aminoaciduria from proximal tubular dysfunction, or after a protein-rich diet. Lower values can reflect low intake or catabolic state. Interpreting this result alongside other amino acids, kidney studies, and clinical history helps identify what is most likely.
Results are interpreted using age-specific reference intervals and the creatinine-corrected format. A single abnormal value does not automatically mean disease. Your care team will consider symptoms, diet, recent illness, growth, medications, and other lab results before deciding on next steps.
If results are higher than expected, your clinician may repeat the test, review diet and supplements, and order related studies such as plasma amino acids, urine organic acids, kidney function tests, or genetic testing. If results are lower than expected, nutritional assessment and review of overall health may be suggested. Very dilute or highly concentrated urine can affect the creatinine ratio, so proper collection and hydration guidance are important.
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.
Recent high protein intake, formula changes in infants, or amino acid supplements can raise urinary histidine. A brief dietary history before collection helps interpret out-of-range results.
Very dilute or very concentrated urine alters the creatinine correction and may skew the ratio. Follow collection instructions carefully and avoid collecting soon after excessive fluid intake.
Drugs that affect the renal tubule, such as certain antivirals, chemotherapeutics, or aminoglycosides, can increase amino acid losses. Prior kidney injury or proximal tubulopathies may show similar patterns.
Fever, infection, trauma, or fasting can change amino acid metabolism and urinary excretion. Testing when you are well often gives a more stable baseline.
Infants and young children naturally excrete different amounts of amino acids than older children and adults. Age-specific interpretation is essential for this test.
Random urine samples are common and normalized to creatinine. In some cases a full-day urine collection or paired plasma amino acids may be requested for clearer interpretation.
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