Threonine Unit Converter
Threonine Unit Converter
Convert threonine between mg/dL and µmol/L, with fasting reference intervals by age — and see why threonine is one of the amino acids read as part of a whole profile rather than alone, starting with two published adult intervals that disagree by more than a hundred µmol/L.
Threonine converter
mg/dL ⇄ µmol/LThreonine 2.80 mg/dL on a fasting plasma amino acid profile, read against the adult interval
Formula and conversion factor
mg/dL = µmol/L ÷ 83.949
- 83.949
- derived from the molecular weight of L-threonine, 119.12 Da
- 325 against 211.6
- Mayo's and Labcorp's adult upper limits. The widest disagreement of any amino acid on this site, and the reason a threonine has to be read against its own laboratory's interval
- read as a profile
- threonine is reported within a quantitative plasma amino acid profile. There is no threonine-specific disorder in routine practice, and an isolated value is interpreted alongside the other amino acids rather than alone
- handling drift
- in whole blood left at room temperature before separation, most amino acid concentrations rise by more than 10% over 24 hours, and the rise is largely prevented by keeping the sample on ice
Worked example
Threonine 2.80 mg/dL on a fasting plasma amino acid profile, read against the adult interval
2.80 × 83.949 = 235.06 µmol/L, reported as 235 µmol/L
Within the Mayo adult interval of 73–325 µmol/L used here — reported as normal
Above Labcorp's adult upper limit of 211.6 µmol/L — reported as raised
Also above Mayo's own 2–17 year upper limit of 205 µmol/L, so the same result in a child would read differently again
One number, three verdicts, and no clinical change between them. This is why the interval that matters is the one printed on the report beside the result, for that age and that laboratory
The widest inter-laboratory disagreement of any amino acid here
| Source | Adult (µmol/L) | Children (µmol/L) | Younger bands (µmol/L) |
|---|---|---|---|
| Mayo Clinic Laboratories — LC-MS/MS, fasting | 73 – 325 (≥18 y) | 48 – 205 (2–17 y) | 49 – 358 (<24 months) |
| Labcorp — plasma amino acid intervals | 67.8 – 211.6 (>15 y) | 55.9 – 192.6 (2–15 y) | 53.3 – 262.3 (31 d–23 m); 60.7 – 326.8 (0–30 d) |
What a raised threonine usually is, and what it is not
| Consideration | How it reads | What to do with it |
|---|---|---|
| Which laboratory’s interval | The commonest reason a threonine looks abnormal at all, given a 113 µmol/L spread between published adult ceilings | Use the interval on the report. Do not compare a result against an interval from elsewhere |
| Sample handling | Non-specific changes arise from haemolysis, delayed separation or transport at room temperature, and most amino acids rise more than 10% over 24 hours | Repeat fasting, separated promptly and kept cold, before interpreting anything |
| Diet and protein intake | Threonine is essential, so plasma levels follow intake, supplements and parenteral nutrition | Take a dietary and nutrition history |
| Drugs | Valproate is associated with raised glycine, alanine and serine in treated children — not with a raised threonine specifically | A drug history is still worth taking; the pattern it produces is read on the glycine and serine pages |
| An isolated abnormality | Threonine has no routine disorder of its own; it is interpreted within the whole profile | Read the full profile with a metabolic service rather than acting on one line of it |
An essential amino acid that is read as part of a pattern
Threonine is an essential amino acid with a molecular weight of 119.12 Da, so 1 mg/dL is 83.95 µmol/L. It is reported within a quantitative plasma amino acid profile — the same assay that measures the branched-chain amino acids, glycine, glutamine and the rest — and it is very rarely requested or interpreted by itself. Being honest about that is the most useful thing this page can do.
Start with the reference intervals, because they are the first reason a threonine looks abnormal. Mayo publishes 73–325 µmol/L for fasting adults; Labcorp publishes 67.8–211.6 µmol/L for anyone over 15. The upper limits differ by 113 µmol/L, the widest such gap of any amino acid on this site, so a result of 235 µmol/L is unremarkable at one laboratory and flagged at the other. Mayo’s own paediatric bands make the point again: the 2–17 year upper limit is 205, lower than both the adult 325 and the under-24-months 358. These are measured population intervals, method- and age-specific, and the one that applies is the one printed beside the result.
The second reason is the sample. Published intervals assume a fasting sample separated promptly. Non-specific changes arise from haemolysis, delayed separation or transport at room temperature, and in whole blood left standing most amino acid concentrations rise by more than 10% over 24 hours — a rise largely prevented by keeping the specimen on ice. Threonine is essential, so it also follows protein intake, supplements and parenteral nutrition. A drug and nutrition history belongs with the result; valproate, often mentioned in this context, is associated with a raised glycine, alanine and serine in treated children rather than with a raised threonine.
What is left is a number that contributes to a pattern. There is no routine threonine disorder to diagnose, no threonine threshold that prompts an action, and no circumstance in which an isolated threonine should change treatment. Where an amino acid profile is abnormal, it is read as a whole by a metabolic service, alongside the clinical picture, the urine organic acids and a properly collected repeat. A converted threonine is a unit change, correctly done, and no more than that.
Frequently asked questions
How do I convert threonine from mg/dL to µmol/L?
Multiply by 83.949, derived from the molecular weight of threonine, 119.12 Da. A threonine of 2.80 mg/dL is 235 µmol/L. To go the other way, divide the µmol/L figure by 83.949.
What is a normal threonine level?
It depends on the laboratory more than for most amino acids. Mayo publishes 73–325 µmol/L for fasting adults and Labcorp 67.8–211.6 µmol/L for anyone over 15 — upper limits 113 µmol/L apart. Paediatric bands differ again. Use the interval your own report prints for that age.
Does a raised threonine mean anything on its own?
Rarely. There is no routine threonine-specific disorder; a modest elevation is usually the laboratory’s interval, a non-fasting or slowly separated sample, or protein intake. Threonine is interpreted as one line of a whole plasma amino acid profile, read with a metabolic service.
Does valproate raise threonine?
The paediatric study usually cited for valproate’s effect on the amino acid profile found raised glycine, alanine and serine in treated children, not a raised threonine. A drug history is still worth taking, but the pattern valproate produces is read on the glycine and serine pages.
Why does the interval for infants look higher than for adults?
Because it is. Mayo publishes 49–358 µmol/L under 24 months, 48–205 µmol/L for 2 to 17 years and 73–325 µmol/L for adults. Amino acid intervals are measured in each age group rather than interpolated, so they are not always monotonic with age.
Related calculators
References
- Mayo Clinic Laboratories. Test ID: AAQP — Amino Acids, Quantitative, Plasma. Liquid chromatography tandem mass spectrometry. Reference values are for fasting patients, in three age bands (under 24 months, 2–17 years, 18 years and over). Accessed 2026.
- Labcorp. Plasma Amino Acid Reference Intervals — four age bands from 0–30 days to over 15 years, µmol/L. Accessed 2026.
- Davis JS, Darcy CJ, Piera K, et al. Ex-vivo changes in amino acid concentrations from blood stored at room temperature or on ice: implications for arginine and taurine measurements. BMC Clin Pathol. 2009;9:10.
- Royal Liverpool and Broadgreen University Hospitals NHS Trust, Department of Clinical Biochemistry and Metabolic Medicine. Amino Acids (Plasma) — user handbook entry: fasting sample preferred; non-specific changes may arise from haemolysis, delayed separation or shipping at room temperature.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.