A 28-year-old gets a sore throat on Monday. By Wednesday, his urine looks like cola. He drinks more water, it clears up, and he forgets about it. Two years later, a work physical shows protein and blood in his urine and a creatinine that is higher than it should be.
That story fits IgA nephropathy (IgAN), also called Berger’s disease. It is the most common primary glomerulonephritis in the world, and it often hides in plain sight for years.
The good news: IgAN treatment changed more between 2021 and 2026 than in the previous 40 years. Here is what patients and families should know.
What Is IgA Nephropathy?
IgA is an antibody that normally guards the lining of your gut and airways. In IgAN, the body makes a faulty version called galactose-deficient IgA1 (Gd-IgA1). The immune system then makes antibodies against that faulty IgA. The two bind into immune complexes that lodge in the mesangium, the support tissue inside each glomerulus.
Those deposits trigger inflammation and complement activation. Over time, the filters scar, protein leaks into the urine and kidney function falls. Doctors describe this as a “four-hit” process, and each hit is now a treatment target.
IgAN belongs to a larger family of conditions our team treats under glomerular disease management.
Who Gets IgAN?
- Most often diagnosed between ages 20 and 40.
- In the United States, men are diagnosed about twice as often as women.
- More common in people of East Asian and European ancestry.
- Family clusters occur, and researchers have linked several genes to higher risk.
Signs and Symptoms of IgA Nephropathy
Many people have no symptoms at all. When signs do show up, they tend to follow one of these patterns.
Visible Blood in the Urine After an Infection
Tea- or cola-colored urine that appears within 1 to 3 days of a cold, sore throat or stomach bug is the classic sign. Doctors call this “synpharyngitic” hematuria. The timing matters, because post-strep kidney inflammation usually shows up 1 to 3 weeks after the infection, not 1 to 3 days.
Hidden Blood and Protein Found on Routine Tests
Microscopic hematuria plus protein on a dipstick is the most common way IgAN is found in adults. Foamy urine can be a clue. Our article on proteinuria as a warning sign of kidney damage explains what those dipstick results mean.
Other Signs
- New high blood pressure in a young adult.
- Swelling in the ankles or around the eyes when protein loss is heavy.
- Rarely, a rapid rise in creatinine with crescents on biopsy, which needs urgent care.
Dark Urine: Is It IgAN or Something Else?
| Clue | IgA Nephropathy | Post-Strep Glomerulonephritis | Kidney Stone | Urinary Tract Infection |
| Timing after infection | 1 to 3 days | 1 to 3 weeks | Not related | Not related |
| Pain | Usually none or mild flank ache | Usually none | Severe, wave-like flank pain | Burning with urination |
| Urine color | Cola or tea colored | Cola colored | Pink or red | Cloudy, sometimes pink |
| Recurs with each cold | Often | Rarely | No | No |
| Complement C3 level | Normal | Low | Normal | Normal |
How IgA Nephropathy Is Diagnosed
No blood test can confirm IgAN. A kidney biopsy is the only way to make the diagnosis. Still, several tests come first, and they shape the treatment plan.
Step 1: Urine Tests
- Urinalysis with microscopy: looks for misshapen (dysmorphic) red blood cells and red cell casts, which point to bleeding from the glomerulus rather than the bladder.
- Urine protein-to-creatinine ratio (UPCR) or 24-hour urine protein: measures how much protein you lose each day. This is the single most important number for prognosis.
Step 2: Blood Tests
- Creatinine and eGFR to measure filtering function.
- Complement levels (C3, C4) and tests for lupus, hepatitis B and C, and HIV to rule out look-alike diseases.
- Serum IgA level. It is high in some patients but is not reliable enough to diagnose IgAN.
Our guide to kidney function tests explains each value on a standard kidney panel.
Step 3: Kidney Biopsy
A needle biopsy takes a few thin cores of tissue, usually as an outpatient procedure with a few hours of observation. The pathologist looks for IgA-dominant deposits in the mesangium on immunofluorescence.
Understanding Your MEST-C Score
Biopsy reports for IgAN include an Oxford MEST-C score. Each letter grades one type of injury:
| Letter | What It Measures | What It Tells Your Doctor |
| M | Mesangial hypercellularity | Level of active inflammation in the support tissue |
| E | Endocapillary hypercellularity | Inflammation inside the capillary loops, may respond to immune therapy |
| S | Segmental sclerosis | Partial scarring of filters |
| T | Tubular atrophy and interstitial fibrosis | Chronic, permanent damage. The strongest predictor of long-term outcome |
| C | Crescents | Aggressive injury that may need urgent treatment |
Your nephrologist combines MEST-C with eGFR, blood pressure and protein loss in the International IgAN Prediction Tool. It estimates your 5-year risk of losing half of your kidney function or reaching kidney failure.
How Serious Is IgA Nephropathy?
For years, IgAN was described as “benign” in many patients. Long-term registry data say otherwise. People with ongoing proteinuria, even at levels once thought safe, face a high lifetime risk of kidney failure. Because IgAN often starts in a person’s 20s or 30s, a slow decline still adds up over decades.
| Risk Profile | Typical Findings | Usual Plan |
| Lower risk | Protein under 0.5 g/day, normal blood pressure, normal eGFR | Monitoring every 6 to 12 months, blood pressure control, lifestyle steps |
| Moderate risk | Protein 0.5 to 1 g/day or mild eGFR loss | Maximal supportive care plus a targeted IgAN therapy |
| High risk | Protein above 1 g/day, falling eGFR, scarring or crescents | Combination therapy and close follow-up every 1 to 3 months |
IgA Nephropathy Treatment: The 2026 Toolkit
The 2025 KDIGO guideline sets a clear goal: get protein loss under 0.5 g per day, and ideally under 0.3 g per day. Treatment now works on two fronts at once. One set of drugs protects the filters from ongoing damage. The other set targets the faulty IgA and the immune response behind it.
Foundation Therapy: Protect the Filters
- ACE inhibitor or ARB at the highest dose you tolerate.
- Blood pressure control, with a systolic target near 120 if you tolerate it. Home readings help, and our guide to monitoring your blood pressure at home shows how to keep a useful log.
- SGLT2 inhibitor such as dapagliflozin or empagliflozin. Trials that included IgAN patients showed slower kidney decline.
- Sparsentan (Filspari) or atrasentan (Vanrafia), endothelin pathway blockers that lower protein loss further. Sparsentan replaces the ARB rather than adding to it.
Disease-Targeted Therapy: Stop the Immune Attack
| Medicine | How It Works | How It Is Given | FDA Status |
| Targeted-release budesonide (Tarpeyo) | Reduces faulty IgA production in gut lymph tissue | Capsule daily for 9 months | Full approval 2023 |
| Iptacopan (Fabhalta) | Blocks factor B in the complement pathway | Capsule twice daily | Accelerated approval 2024 |
| Sibeprenlimab (Voyxact) | Blocks APRIL, a signal that drives faulty IgA | Injection under the skin every 4 weeks | Accelerated approval 2025 |
| Systemic steroids | Broad immune suppression | Pills for several months, often at reduced doses | Used selectively due to side effects |
| Dual BAFF/APRIL blockers | Block two signals that drive faulty IgA | Injection | Newest class, ask about current status |
Not every patient needs every drug. A young adult with low protein loss may do well on foundation therapy alone. A patient with heavy proteinuria and active inflammation on biopsy often needs a targeted agent early. Insurance approval for these newer drugs usually requires biopsy proof and a documented UPCR, so complete records speed things up.
Lifestyle Steps That Make Medicines Work Better
- Keep sodium under 2,000 mg a day. Salt blunts the effect of ACE inhibitors and ARBs.
- Avoid NSAIDs such as ibuprofen and naproxen.
- Stop smoking and vaping.
- Reach a healthy weight, which lowers pressure in the filters.
- Get vaccines on schedule, since infections can trigger flares.
IgAN Care for Patients in Southern Oklahoma and North Texas
Young adults with IgAN often work outdoors, in oil fields, on ranches or in construction. Dark urine after a hot shift gets blamed on dehydration. If dark urine follows a cold or sore throat, or keeps coming back, get a urinalysis instead of guessing.
Distance is the other barrier. Specialty drugs need regular UPCR and potassium checks. We schedule labs with clinic visits and coordinate with specialty pharmacies so patients in rural counties do not miss doses or monitoring.
What Happens if IgAN Reaches Kidney Failure?
With today’s treatments, many patients will never get there. For those who do, kidney transplant is the preferred option. IgA deposits can return in the new kidney, yet graft loss from recurrence is far less common than the deposits themselves. Our kidney transplant patient care team helps with referral, preparation and long-term follow-up.
Frequently Asked Questions
Is IgA nephropathy genetic?
Genes raise the risk, and family clusters exist, but most cases are not inherited in a simple pattern. Our article on rare kidney diseases and genetic disorders explains when genetic testing makes sense.
Can IgA nephropathy go into remission?
Yes. Some patients reach protein levels under 0.3 g per day and keep stable eGFR for many years. Remission still needs monitoring, since flares can follow infections.
Is IgAN the same as nephrotic syndrome?
No. Most IgAN patients have a nephritic pattern with blood and moderate protein in the urine. A small number develop heavy protein loss. Our article on nephrotic syndrome warning signs covers that pattern.
How often will I need labs?
Expect urine protein, creatinine and potassium checks every 1 to 3 months during active treatment, then every 3 to 6 months once stable.
Get Answers From a Kidney Specialist
Blood in the urine after a cold, protein on a routine test or new high blood pressure in your 20s or 30s all deserve a closer look. Early treatment protects function you cannot get back later.
Meet the nephrology team at Southern Oklahoma Kidney Center in Ardmore, Ada and Gainesville. Our first visit guide explains what to bring. Call (580) 223-8614 or book a consultation today.
This article is for education only and does not replace advice from your own doctor.
