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CSF Threonine

Body Fluids

Cerebrospinal fluid threonineCSF Thr

Review status

Currently under review

Pending specialist review and validation.

What it shows

The CSF Threonine test measures the amount of threonine, an essential amino acid, in your cerebrospinal fluid. Cerebrospinal fluid surrounds and protects the brain and spinal cord, so its composition can reflect what is happening within the central nervous system more directly than a blood test.

Threonine is involved in protein synthesis and several metabolic pathways. Measuring it in CSF can help your care team assess how amino acids are transported and used in the brain, and whether a metabolic or neurologic condition is affecting these processes.

Why it matters

Your clinician may order this test when there are unexplained neurologic symptoms, concerns for a metabolic disorder, or when patterns of amino acids in the brain need to be evaluated. CSF threonine is often reviewed alongside other CSF amino acids to look for characteristic patterns that point toward inborn errors of metabolism, problems with nutrient transport, or effects of illness.

Abnormal results can support further evaluation for genetic metabolic conditions, guide treatment decisions, or help monitor response to diet and therapies. Results can also be influenced by diet, medications, and systemic illness, so the test is interpreted together with your history, examination, and other laboratory studies.

Understanding your results

Your result is interpreted in the context of the full CSF amino acid profile, your symptoms, and any related blood and urine tests. A value that is higher or lower than expected does not automatically mean disease; it can reflect sample handling issues, recent diet, or medications. Your clinician will consider whether there was blood contamination during the spinal tap and whether the pattern matches a known metabolic or neurologic process.

If results are unexpected, your care team may recommend confirming the finding, comparing with plasma amino acids, checking urine metabolites, or pursuing genetic testing. Do not change your diet or supplements without medical guidance. Discuss any medications and nutrition plans with your clinician so results can be interpreted accurately and follow-up can be tailored to you.

Reference ranges

545 umol/L
All sexes
0 days – 150 years

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.

Factors that could impact CSF Threonine

  • Sample handling and timing

    Delays in processing, improper storage, or lack of prompt freezing can alter amino acid levels in CSF. Rapid processing, correct tube selection, and transport on ice help ensure accurate measurements.

  • Blood contamination

    A traumatic lumbar puncture or mixing with blood can artificially change CSF amino acid levels. Your clinician will often review the red blood cell count in CSF to judge whether contamination affected interpretation.

  • Diet and fasting status

    Recent high protein intake, fasting, ketogenic diets, or total parenteral nutrition can shift amino acid patterns. Sharing detailed dietary information helps the lab and clinician interpret results appropriately.

  • Medications and supplements

    Drugs that affect nitrogen metabolism or mitochondrial function, such as valproate, and high dose amino acid or protein supplements can influence results. Provide a complete medication and supplement list.

  • Age and developmental stage

    CSF composition varies with age, especially in infants and young children. Age-appropriate reference intervals and clinical context are essential for accurate interpretation.

  • Concurrent illness

    Infection, inflammation, liver dysfunction, renal impairment, or recent neurologic events can affect CSF amino acids. Let your clinician know about any recent illnesses or procedures.

2026

References

  1. McGill University Health Centre. (2006, September 13). CSF Threonine (Task CD 693389). Laboratory reference ranges.
  2. ARUP Consult. (2024). Amino acids, quantitative, cerebrospinal fluid. ARUP Laboratories. External link
  3. British Inherited Metabolic Disease Group. (2021). Guidelines for the investigation of suspected inborn errors of metabolism in neurology. External link