Platform
Company
Urinalysis
Review status
Currently under review
Pending specialist review and validation.
This test measures the amount of threonine, an essential amino acid, in a urine sample. Results are usually normalized to creatinine to adjust for how concentrated or dilute the urine is, which makes results easier to compare between people and across different collection times.
Urine threonine is often assessed as part of a broader amino acid profile to help evaluate metabolic health. It can be useful in infants, children, and adults when there is a concern for an inherited metabolic condition, kidney tubular dysfunction, or nutrition issues, and it may be used to monitor response to treatment or dietary changes.
Unusual urine threonine levels can be a clue to how the body is processing proteins. Changes may occur with inherited metabolic disorders that affect amino acid handling, kidney tubular problems that cause amino acids to spill into urine, liver dysfunction, malabsorption, or periods of illness and catabolic stress. Because threonine is essential, inadequate intake or poor absorption can also influence results.
Clinicians may order this test when there are symptoms such as poor growth, feeding problems, vomiting, developmental concerns, unexplained acidosis, or signs of kidney issues. It is also used alongside blood amino acids, organic acids, and other studies when following up an abnormal newborn screen or monitoring nutrition support in medically fragile patients.
Your report is interpreted using age specific reference intervals and the context of your health. A single value is most useful when viewed together with other amino acids and clinical information. Small shifts outside the expected range can occur with recent diet changes, illness, or variations in urine concentration, even when a creatinine correction is applied.
If your result is higher or lower than expected, your clinician may confirm with a repeat sample, review diet and supplements, and consider additional tests such as plasma amino acids, urine organic acids, kidney and liver panels, or genetic testing. Proper collection and avoiding contamination help ensure that the number reflects your biology rather than a preanalytic issue.
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.
Very dilute or very concentrated urine can influence amino acid to creatinine ratios. Low muscle mass can also affect creatinine and shift results.
Recent high protein intake, fasting, fever, or catabolic stress can change amino acid excretion patterns and may transiently raise or lower threonine.
Amino acid supplements, protein powders, parenteral nutrition, and some medications such as anticonvulsants or chemotherapy agents can alter amino acid handling.
First morning versus random samples, diaper or container contamination, and delays in transport or freezing can affect measured amino acids.
Kidney tubular disorders may cause generalized aminoaciduria, and liver disease can change amino acid metabolism, both influencing urine threonine.
Infants, preterm babies, and pregnant patients can have different amino acid patterns. Age specific interpretation is important for accurate assessment.
References