IgA nephropathy
The most common form of glomerulonephritis, in which an antibody called IgA builds up in the kidney's filters and inflames them. It often shows up as blood in the urine — sometimes visible during a cold — and, over years, can slowly damage the kidneys.
What it is
IgA nephropathy (also called Berger disease) is a kidney condition in which deposits of an antibody called immunoglobulin A (IgA) collect in the glomeruli — the kidney's tiny filtering units — triggering inflammation that damages them. It is the most common glomerulonephritis worldwide. A classic presentation is an episode of visible blood in the urine that appears within a day or two of an upper respiratory infection such as a cold or sore throat, most often in a young adult. More commonly, it is found by chance when a urine test shows microscopic blood, sometimes with protein, in someone without symptoms. Over the long term, IgA nephropathy varies greatly: many people keep stable kidney function for life, but a proportion slowly develop rising protein in the urine, high blood pressure and a gradual decline in kidney function, and some eventually reach kidney failure. The diagnosis is confirmed by a kidney biopsy showing IgA deposits. Management focuses on the factors that drive progression — controlling blood pressure and reducing protein in the urine (often with medicines that also protect the kidney), and in selected cases treatments that damp down the immune process — with long-term monitoring of kidney function and urine protein.
Key lab markers
- Urinalysis — the hallmark is blood in the urine (microscopic or visible), often with protein.
- Urine protein / protein-creatinine ratio — the amount of protein loss predicts progression.
- Creatinine and eGFR — track kidney function over time.
- Blood pressure — high blood pressure both results from and worsens the condition.
- Kidney biopsy — confirms the diagnosis by showing IgA deposits.
Symptoms
- Visible blood in the urine, classically during or just after a cold or sore throat
- Microscopic blood in the urine found on testing (often no symptoms)
- Foamy urine if protein loss is significant
- High blood pressure
- Swelling of the legs or around the eyes if protein loss is heavy
- Often no symptoms at all for years
Related lab panels
When to discuss with a doctor
IgA nephropathy is usually a slowly evolving condition, and its outlook depends a great deal on controlling the factors that drive it — so it rewards steady, long-term care rather than urgent action. If a urine test shows blood or protein, or you notice visibly bloody urine (especially around the time of a cold), it is worth following up, as this can be the first clue. Once diagnosed, keeping blood pressure well controlled and reducing protein in the urine are the most important things you can do to protect the kidneys over the years, alongside regular monitoring. Rapidly worsening kidney function or heavy new swelling should prompt prompt review. Mediora.AI can surface the pattern of blood and protein in the urine with kidney function that fits IgA nephropathy; the diagnosis rests on a biopsy and the ongoing care belongs with your kidney specialist.