Urine Protein Unit Converter
Urine Protein Unit Converter
Convert a 24-hour urine total protein between mg/24 h, mg/d and g/24 h — and see why there is no mg/dL and no µmol/L to convert it into.
Urine Protein converter
Mass ladder onlyA 24-hour urine protein reported as 0.12 g
The conversions that exist, and the ones that do not
mg/d = mg/24 h (the same quantity, two spellings)
mg/24 h = concentration in mg/L × collection volume in litres
no µmol/24 h exists — see below
- no molar unit
- urine protein is albumin, immunoglobulin light chains, Tamm-Horsfall protein and the low-molecular-weight tubular proteins in a proportion that changes with the disease, so there is no grams per mole to divide by
- mg/dL is a different quantity
- a concentration, not a daily excretion; relating the two needs the measured volume, which is why this ladder does not offer both
- mg/g or mg/mmol creatinine
- the protein-creatinine ratio, a third quantity again — it needs the creatinine on the same specimen
Worked example
A 24-hour urine protein reported as 0.12 g
0.12 × 1,000 = 120 mg/24 h
= 120 mg/d, which is the same number in ARUP's spelling
Within ARUP's 40–150 mg/d and Labcorp's 30–150 mg/24 h, and well within Mayo's upper limit of 229 mg/24 h
There is no µmol figure to report: the measurand is a mixture, not a molecule
24-hour urine protein: the published intervals disagree by half again
| Source | Interval | Unit |
|---|---|---|
| ARUP, 24-hour urine protein | 40 – 150 | mg/day |
| Labcorp 003277, adult | 30 – 150 | mg/24 h |
| Mayo PTU, 18 years and over | < 229 | mg/24 h |
| Nephrotic-range proteinuria | > 3,500 | mg/24 h |
| ARUP protein/creatinine, adult male | 15 – 68 | mg/g creatinine |
| ARUP protein/creatinine, adult female | 10 – 107 | mg/g creatinine |
Why there is no molar conversion for urine protein
| Component | Approximate mass | Why it rules a single factor out |
|---|---|---|
| Albumin | 66.5 kDa | The dominant protein in glomerular disease, but not in tubular disease |
| Immunoglobulin free light chains | 23 kDa monomer, 46 kDa dimer | Kappa and lambda differ, and so does the monomer-dimer mix |
| Tamm-Horsfall protein (uromodulin) | about 85 kDa | Secreted by the tubule, so present in health and variable |
| Beta-2 microglobulin, retinol-binding protein, alpha-1 microglobulin | 11.7 – 26 kDa | The tubular markers; they dominate in proximal tubular injury |
| The measurand | no single value | The proportions change with the disease, so grams per mole is not defined |
One test, three quantities, and no molar unit
A 24-hour urine total protein is an amount per collection. It is not the same quantity as a protein concentration in mg/dL, and it is not the same quantity as a protein-creatinine ratio in mg/g or mg/mmol — each needs something the others do not have, a volume in the first case and a creatinine in the second. The three are routinely quoted as if they were interchangeable, and they are not: that is why this converter offers only the per-24-hour family, and why the protein-creatinine ratio calculator and the estimated 24-hour protein calculator are separate tools rather than extra rows here.
There is also no molar unit, and that is not an omission. Urine protein is a mixture — albumin, immunoglobulin free light chains, uromodulin, and the low-molecular-weight proteins the proximal tubule normally reclaims — in a proportion that is itself the diagnostic information. Glomerular disease shifts it towards albumin; proximal tubular injury shifts it towards beta-2 microglobulin and alpha-1 microglobulin; myeloma shifts it towards free light chains that a dipstick will not see at all. Dividing a mixture by an assumed molar mass produces a number with no referent, so any source offering µmol/L for total urine protein has made one up. For the blood-side equivalent see the serum total protein converter, which is mass-only for the same reason.
The reference intervals disagree more than most readers expect. ARUP gives 40 to 150 mg/day and Labcorp 30 to 150 mg/24 h, while Mayo gives under 229 mg/24 h — half again as high, and with no lower limit. A result of 200 mg/24 h is therefore reported as normal by one large reference laboratory and abnormal by two others, which is worth knowing before treating a single borderline figure as a change in disease.
Two interpretive points. Total protein and albumin are not substitutes: albuminuria is the better marker of glomerular disease and of cardiovascular and renal risk, which is why KDIGO stages chronic kidney disease on albumin rather than protein — see the albumin-creatinine ratio and the KDIGO albuminuria categories. But total protein catches what albumin misses, including light chains and tubular proteinuria. And the collection itself is part of the result: an incomplete bottle understates proteinuria in exact proportion to how much was missed.
Frequently asked questions
Can urine protein be converted to µmol/L?
No, and a source offering that conversion has assumed a molecular weight that does not exist. Urine protein is a mixture of albumin, light chains, uromodulin and tubular proteins whose proportions change with the disease, so there is no single grams per mole to divide by. Mass units only.
How do I convert urine protein from mg/24 h to g/24 h?
Divide by 1,000. A 24-hour protein of 120 mg is 0.12 g, and nephrotic-range proteinuria of 3,500 mg is 3.5 g. mg/d and mg/24 h are the same quantity written two ways — ARUP prints the first, Mayo and Labcorp the second.
Why does Mayo’s normal range go up to 229 mg/24 h when others stop at 150?
Because they derived the interval differently. Mayo publishes under 229 mg/24 h for adults with no lower limit; ARUP gives 40 to 150 mg/day and Labcorp 30 to 150 mg/24 h. The 150 mg figure is the long-standing textbook limit. A result between 150 and 229 is normal or abnormal depending only on which laboratory ran it.
Can I convert a urine protein concentration in mg/dL into a daily excretion?
Only with the measured collection volume: mg/24 h equals the concentration in mg/L multiplied by the volume in litres. Without the volume a concentration is mostly a statement about how dilute the urine was. If no timed collection is available, use the protein-creatinine ratio instead, which corrects for dilution.
Should I measure total protein or albumin?
Albumin for staging and risk in chronic kidney disease, which is what KDIGO uses. Total protein when you need to catch what albumin misses — immunoglobulin free light chains in myeloma, and the low-molecular-weight proteins of tubular injury. A large gap between total protein and albumin is itself the clue.
Related calculators
References
- ARUP Laboratories. Protein, total, urine — 24-hour and protein/creatinine ratio reference intervals. Laboratory Test Directory 0020479; 2026.
- Labcorp. Protein, total, quantitative, 24-hour urine — test 003277, reference interval. Test menu; 2026.
- Mayo Clinic Laboratories. Protein, total, 24 hour, urine (PTU) — reference values. Test catalogue, test ID 614001; 2026.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int. 2024;105(4S):S117–S314.
Not medical advice. For healthcare professionals and education. Reference intervals vary by laboratory and assay — always use your own laboratory's. Never base a dose or a treatment decision on this page alone. Full disclaimer at calcengines.com/disclaimer/