L-Homoserine-to-Creatinine Ratio, Urine
Measures urinary L-homoserine relative to creatinine, helping evaluate amino acid metabolism and account for differences in urine concentration.
["This urine test measures L-homoserine excretion and may help investigate certain rare inherited metabolic disorders."]
Key facts at a glance
- LOINC
- 79644-1
- Short code
- L-homoserine/Creat Ur-sRto
- Synonyms
- L-homoserine/Creat Ur-sRto
- Category
- kidney
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 1.5
- Ref high
- 9
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 83002
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test measures L-homoserine, an amino acid, in your urine. The result is compared with the amount of creatinine in the same sample, which helps account for variations in urine concentration.
Why might I need this test?
L-homoserine testing may be used when symptoms or family history suggest a rare inherited problem with amino acid metabolism. It is often part of a broader evaluation for metabolic disease.
How is the test performed?
A urine sample is collected and analyzed in a laboratory. The laboratory measures L-homoserine and creatinine and reports their ratio, so the result is not strongly affected by how concentrated or dilute the urine is.
How do I prepare for the test?
Follow your clinician's urine-collection instructions, including whether a first-morning or timed sample is required. Tell the laboratory if you are taking supplements or medications that contain amino acids or otherwise may affect the result.
Reference range
Follicular: 1.5-9.0 mIU/mLN/A
For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An elevated urinary L-homoserine-to-creatinine ratio may indicate increased loss of L-homoserine and can occur in rare inherited disorders of amino acid metabolism, including homoserine kinase deficiency. Interpretation depends on symptoms, age, diet, medications, and the results of other metabolic tests. An isolated result should not be used to diagnose a condition without clinical evaluation.
Short name
Urinary L-Homoserine
Frequently asked questions
What does the urine L-homoserine-to-creatinine ratio measure?
Does this test require a fasting blood draw?
What can cause an elevated result?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy