Platform
Company
Urinalysis
Review status
Currently under review
Pending specialist review and validation.
The Urine Methionine test measures the amount of the essential amino acid methionine in your urine, adjusted to creatinine to account for how concentrated the urine is. Methionine is a building block of proteins and a key participant in methylation and sulfur pathways that help your body make and recycle important compounds. You get methionine from your diet, and your body converts it into related molecules, including homocysteine and cysteine.
This test is commonly performed as part of a urine amino acid profile to evaluate how your body handles amino acids. It can help screen for or monitor inherited metabolic conditions, assess nutritional influences, and provide context when there are concerns about liver function or unusual amino acid losses. It is noninvasive and typically uses a clean-catch urine sample.
Abnormal urinary methionine can signal disruptions in methionine metabolism. These may occur with rare genetic conditions that affect methionine processing, with liver disease, malnutrition, or with excessive use of supplements containing methionine or related compounds. Clinicians interpret methionine together with other amino acids and your clinical history, since patterns across several results are often more informative than a single value.
Your clinician may order this test to follow up an abnormal newborn screen, investigate unexplained developmental concerns or poor growth, evaluate abnormal liver tests, or monitor known amino acid disorders and dietary therapy. Results can also inform evaluation of vitamin status, particularly folate, vitamin B6, and vitamin B12, which influence methionine pathways.
Your result is compared with an age-specific expected range and adjusted for urine creatinine. A higher-than-expected value can be related to high protein or supplement intake, reduced conversion of methionine due to genetic or acquired conditions, or changes in kidney handling. A lower-than-expected value is less commonly concerning and may reflect low protein intake or very dilute urine. The overall amino acid pattern, your symptoms, and medical history guide interpretation.
Hydration affects urine concentration. Very dilute urine from high fluid intake or very concentrated urine from dehydration can shift results, even when corrected to creatinine. If a result is unexpected, your clinician may repeat testing, review collection technique, and consider additional evaluations such as plasma amino acids, total homocysteine, vitamin levels, liver tests, or genetic assessment. Do not change your diet or supplements unless your clinician advises it.
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.
Creatinine adjustment helps, but very dilute urine from high fluid intake or very concentrated urine from dehydration can still influence the measured methionine-to-creatinine ratio.
High protein meals, specialty diets, protein shakes, or supplements containing methionine or S-adenosylmethionine can raise urinary methionine. Low protein intake may reduce it.
Drugs that affect liver function or vitamin pathways, and liver disease itself, can alter methionine metabolism and excretion. Tell your clinician about all medicines and over-the-counter products.
Infants and young children naturally have different amino acid handling than adults, and periods of rapid growth can change excretion patterns. Age-specific interpretation is essential.
A clean-catch sample reduces contamination. First-morning or consistently timed collections improve comparability. Spillage, prolonged room-temperature storage, or contamination can skew results.
Because results are indexed to creatinine, reduced kidney function or very low muscle mass may affect the ratio and should be considered when interpreting the value.
References