Myoglobin Unit Converter
Myoglobin Unit Converter
Convert myoglobin between µg/L, ng/mL, mg/L and nmol/L. Myoglobin is the first marker to rise after myocardial injury and the least specific — skeletal muscle, rhabdomyolysis and poor renal clearance all raise it.
Myoglobin converter
Mass ⇄ molarMyoglobin 45 µg/L in an adult man
The four units
mg/L = µg/L ÷ 1000
nmol/L = µg/L × 0.0586407
Derived from a mature molecular weight of 17,053 Da
- µg/L = ng/mL
- a microgram per litre and a nanogram per millilitre are the same concentration. Most laboratories report one or the other and the numbers do not change
- 17,053 Da, not 17,184
- UniProt P02144 lists 17,184 for the 154-residue translated sequence, but the same entry records the initiator methionine as removed and the chain as residues 2–154. The circulating protein is 153 residues at about 17,053 Da, and that is the mass the molar factor is derived from
- nmol/L is a textbook unit
- it appears in SI conversion tables but no laboratory issues myoglobin this way. It is offered here because readers meet it in those tables, not because a report will show it
- mg/L for rhabdomyolysis
- serum myoglobin in rhabdomyolysis runs into the thousands of µg/L, where mg/L is easier to read. Urine myoglobin, when it is measured at all, is usually reported in mg/L
Worked example
Myoglobin 45 µg/L in an adult man
45 µg/L = 45 ng/mL — the same number in the other convention
45 ÷ 1000 = 0.045 mg/L
45 × 0.0586407 = 2.64 nmol/L, a conversion you will meet in tables and never on a report
Within the quoted adult male interval of 25–70 µg/L, and within the female interval of 25–60 µg/L
A normal myoglobin drawn within an hour or two of symptom onset means very little: the marker rises early, but it has not necessarily risen yet
Why myoglobin rises first and means least
| Property | Myoglobin | High-sensitivity troponin |
|---|---|---|
| Time to rise after myocardial injury | 1 – 3 hours | 1 – 3 hours |
| Peak | 6 – 9 hours | 12 – 48 hours |
| Back to baseline | Around 24 hours | 7 – 14 days |
| Molecular weight | About 17 kDa — small, so it leaves damaged cells quickly | Larger, and partly structurally bound |
| Cardiac specificity | None. Identical protein in skeletal muscle | High |
| Cleared by | The kidney — so renal impairment raises it | Multiple routes |
| Current role in suspected infarction | Largely displaced by high-sensitivity troponin | The diagnostic marker |
Causes of a raised myoglobin
| Category | Examples |
|---|---|
| Skeletal muscle injury | Crush injury, prolonged immobility or a long lie, burns, compartment syndrome, surgery |
| Exertional and metabolic | Intense or unaccustomed exercise, seizures, delirium tremens, hyperthermia, severe hypothyroidism |
| Rhabdomyolysis | Statins and other drugs, alcohol, illicit stimulants, inherited metabolic myopathies, sepsis |
| Inflammatory myopathy | Polymyositis, dermatomyositis, immune-mediated necrotising myopathy |
| Reduced clearance | Acute kidney injury and chronic kidney disease — myoglobin is renally cleared, so a raised value can reflect the kidney rather than the muscle |
| Iatrogenic | Intramuscular injections, cardioversion, recent surgery |
| Myocardial injury | Infarction, myocarditis, cardiac contusion — the one cause this marker cannot distinguish from all the others |
First to rise, first to be dropped
Myoglobin is a small haem protein, about 17 kilodaltons, that stores oxygen inside muscle cells. Because it is small and sits free in the cytoplasm rather than bound to a structure, it escapes from damaged muscle faster than anything else measured in a cardiac panel: it begins to rise one to three hours after myocardial injury, peaks at six to nine hours, and is back to baseline by about twenty-four. That speed was its entire clinical appeal.
The problem is that the myoglobin in cardiac muscle and the myoglobin in skeletal muscle are the same protein, so the test cannot tell them apart. A raised myoglobin follows a crush injury, a long lie, a seizure, a marathon, a compartment syndrome, an intramuscular injection, an inflammatory myopathy or any cause of rhabdomyolysis just as reliably as it follows a myocardial infarction. It is also cleared by the kidney, so chronic kidney disease and acute kidney injury raise it without any new muscle damage at all. A single raised myoglobin, on its own, narrows nothing.
High-sensitivity cardiac troponin assays removed the one advantage myoglobin had. They detect myocardial injury on the same one-to-three-hour timescale, and they are cardiac-specific, so the early marker is now also the specific one. Myoglobin’s remaining role in suspected infarction is a multi-marker early rule-out in services that use one, and even there it adds little to a modern troponin pathway; a normal myoglobin drawn very early does not exclude anything, because the value may simply not have risen yet.
Where the measurement still earns its place is muscle rather than heart. In rhabdomyolysis, myoglobin filtered by the glomerulus is directly toxic to the renal tubule, which is the mechanism by which crush injury and severe muscle breakdown cause acute kidney injury. Even there, total creatine kinase is usually the marker followed, because it remains raised for days while myoglobin has cleared within a day — a normal myoglobin in someone who was found on the floor yesterday says nothing about how much muscle was destroyed. Units are the one thing this page can settle outright: µg/L and ng/mL are the same number, mg/L is a thousand times larger, and the reference interval to trust is the one printed beside your own result.
Frequently asked questions
Is µg/L the same as ng/mL for myoglobin?
Yes, exactly the same number. A microgram per litre and a nanogram per millilitre are the same concentration, so a myoglobin of 45 µg/L is 45 ng/mL. Milligrams per litre are a thousand times larger, so the same result is 0.045 mg/L.
What is a normal myoglobin level?
One laboratory publishes 25–70 µg/L for adult men and 25–60 µg/L for adult women; another quotes 28–84 µg/L with no sex split. Intervals are not harmonised between methods, so use the range printed on your own report rather than a figure from anywhere else.
Does a raised myoglobin mean a heart attack?
No. Myoglobin is not cardiac-specific — the identical protein is in skeletal muscle. Exercise, seizures, a fall or long lie, crush injury, rhabdomyolysis, inflammatory myopathy, intramuscular injections and impaired renal clearance all raise it. A cardiac troponin is the test that answers this question.
Is myoglobin still used to diagnose myocardial infarction?
Largely not. Its one advantage was rising within one to three hours, and high-sensitivity troponin assays now detect myocardial injury on the same timescale while being cardiac-specific. Some services still use myoglobin as part of a multi-marker early rule-out, but it adds little to a modern troponin pathway.
Why does myoglobin have a nmol/L conversion when troponin does not?
Because myoglobin has a defined molecular weight — about 17,053 daltons for the mature 153-residue protein — so a molar figure can be derived exactly. Troponin is measured against an assay-specific calibrator rather than a molar standard, so no molar unit exists for it. In practice no laboratory reports myoglobin in nmol/L either; it is a conversion-table unit.
Related calculators
References
- StatPearls. Serum Myoglobin. StatPearls Publishing; NCBI Bookshelf NBK470441.
- UniProt Consortium. UniProtKB entry P02144 (MYG_HUMAN), myoglobin: chain 2–154, initiator methionine removed. Accessed 2026.
- Chan D, Ng LL. Biomarkers in acute myocardial infarction. BMC Med. 2010;8:34.
- Bosch X, Poch E, Grau JM. Rhabdomyolysis and acute kidney injury. N Engl J Med. 2009;361(1):62–72.
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.