24-hour urine protein
A test that measures the total amount of protein leaking into the urine over a full day, collected in one container. It quantifies how much protein the kidneys are losing — an important sign of kidney damage — and defines the heavy 'nephrotic range' loss.
What it measures
Healthy kidneys keep most protein in the blood, allowing only a tiny amount into the urine. When the kidneys' filters are damaged, protein leaks through — proteinuria — and the amount reflects how much damage there is. The 24-hour urine protein test measures the total protein lost over an entire day: all urine passed in 24 hours is collected in a single container, and the lab measures the total protein in it. Normally less than about 150 mg is lost per day. A raised result signals that protein is escaping through damaged kidney filters, as in many kidney diseases (glomerulonephritis, diabetic kidney disease, and others), and the size of the number matters — a loss above roughly 3.5 grams per day is called the 'nephrotic range', a heavy leak that causes the swelling and low blood albumin of nephrotic syndrome. Historically the 24-hour collection was the gold standard for quantifying and monitoring proteinuria. In routine practice it is increasingly replaced by a simpler spot urine protein-to-creatinine or albumin-to-creatinine ratio, which estimates the daily loss from a single sample without the inconvenience of a full-day collection, but the timed collection is still used when precise quantification is needed.
What a high value can mean
- Significant proteinuria — protein leaking through damaged kidney filters.
- Nephrotic-range proteinuria (>3.5 g/24h) — a heavy leak causing swelling and low blood albumin.
- Glomerular kidney disease — such as glomerulonephritis or IgA nephropathy.
- Diabetic or hypertensive kidney damage.
- Pre-eclampsia in pregnancy — proteinuria with high blood pressure.
What a low value can mean
- Normal (<150 mg/24h) — the expected result; the kidney filters are holding protein back.
- A falling level on treatment — suggests the kidney condition or its cause is responding.
When to discuss with a doctor
A 24-hour urine protein test is used to measure precisely how much protein the kidneys are losing, most often after a dipstick or spot ratio has already flagged protein in the urine, and to monitor a known kidney condition over time. It matters because the amount of protein loss is both a marker of kidney damage and a predictor of how the kidneys will fare — and a very heavy (nephrotic-range) loss defines a syndrome that needs specific care. A full-day collection must be done correctly (all urine over 24 hours) for the result to be accurate, which is why the simpler spot ratio is often used instead. Mediora.AI shows the 24-hour protein alongside the spot ratios, albumin and kidney function so the proteinuria picture is read together; the interpretation belongs with your doctor.