Berger’s disease is the most common inflammatory kidney condition in the world, and most people discover it after a routine urine test shows blood or protein that should not be there. Doctors also call it IgA nephropathy, because it develops when a protein called immunoglobulin A collects inside the kidney’s tiny filters. Many people carry the condition for years while feeling perfectly well, which is exactly why lab numbers matter so much here.
In this article you’ll learn how Berger’s disease behaves, which symptoms deserve attention, and how urine and blood tests point toward a diagnosis. We cover the tests kidney specialists rely on, what a biopsy adds, how treatment has changed since 2023, and the questions worth raising at your next appointment. We also clear up the frequent mix-up with Buerger’s disease, a different illness with an almost identical name.
What Berger’s disease is, in plain terms
Each kidney holds roughly a million microscopic filters called glomeruli. Blood passes through them, waste and excess water leave as urine, and useful proteins and blood cells stay behind. In Berger’s disease, an abnormal form of immunoglobulin A circulates in the blood, the immune system tags it as foreign, and the resulting clumps lodge in the mesangium, the supporting tissue at the center of each filter. The kidney reacts with low-grade inflammation. Over years, that inflammation can leave scar tissue and slowly reduce filtering capacity.
It is the most common primary glomerular disease worldwide. Mayo Clinic notes that it usually appears between the mid-teens and mid-thirties, and that in North America and Western Europe men are affected about twice as often as women. Rates are markedly higher in East Asia, partly because several countries screen young people with routine urine dipsticks and so catch silent cases missed elsewhere.
Berger’s disease does not progress uniformly. Some people keep stable kidney function for decades with nothing more than blood pressure control and monitoring, while Cleveland Clinic reports that roughly one in four adults eventually reaches kidney failure requiring dialysis or a transplant. The best predictor of which path someone is on is not how they feel, but how much protein their kidneys leak over time.
Berger’s disease is not Buerger’s disease
The two names sound identical when spoken and are constantly confused. They share nothing beyond spelling. Berger’s disease is an immune kidney disorder named after French pathologist Jean Berger, while Buerger’s disease is a blood vessel disorder of the arms and legs, tightly linked to tobacco use, named after American physician Leo Buerger. The comparison below keeps the two separate.
| Feature | Berger’s disease (IgA nephropathy) | Buerger’s disease (thromboangiitis obliterans) |
|---|---|---|
| Organ affected | The kidneys, specifically the filtering units | Small and medium arteries and veins of the hands and feet |
| What goes wrong | Immune complexes containing immunoglobulin A settle in the kidney filters | Inflammation and clots block blood flow to the limbs |
| Main risk factor | Genetic and immune predisposition; family history in some cases | Tobacco use, which is present in nearly every case |
| Typical signs | Blood or protein in the urine, foamy urine, swelling, rising blood pressure | Pain in fingers and toes, cold sensitivity, ulcers, tissue loss |
| Tests that point to it | Urinalysis, protein-to-creatinine measurements, creatinine and eGFR, kidney biopsy | Vascular imaging, angiography, clinical examination of the limbs |
| Age at onset | Often teens to mid-thirties | Usually under 45, almost always in smokers |
Symptoms and early signs
The hallmark presentation of Berger’s disease is visible blood in the urine within a day or two of a sore throat, cold, or gastrointestinal infection. Urine turns pink, tea-colored, or the shade of cola, and then clears again over a few days. This timing is characteristic: unlike a urinary tract infection, where bleeding follows the infection by a week or more, here the two arrive almost together. Many people describe several such episodes years apart before anyone investigates.
Outside those episodes Berger’s disease is often silent, with blood present only in quantities a laboratory can detect. That is why routine screening picks up so many cases. When symptoms do appear, they typically include:
- Foamy or bubbly urine that persists after flushing, a sign that protein is leaking through the filters
- Swelling in the ankles, feet, hands, or around the eyes, especially at the end of the day
- Dull pain in the back below the ribs
- Blood pressure that starts climbing in someone with no previous history of it
- Unusual tiredness or reduced appetite as kidney function declines
Because the visible episodes come and go, people often assume the problem resolved itself. It rarely does: the quiet phase between episodes is when scarring accumulates, and lab monitoring is the only reliable signal during it. Anyone who has seen blood in their urine even once deserves follow-up testing, and many patients later review a hematuria test result to understand what the laboratory detected.
Why immunoglobulin A builds up in the kidneys
Researchers describe Berger’s disease as a chain of four steps. The body produces an unusual immunoglobulin A that is missing part of its normal sugar coating. The immune system recognizes that bare patch and makes antibodies against it. The two stick together into immune complexes circulating in the blood. Those complexes then deposit in the kidney filters and trigger inflammation. Each step alone causes no harm; the full sequence is what causes disease.
The abnormal immunoglobulin A originates largely in the mucous membranes of the throat and gut, which explains why flare-ups follow infections at those sites, and why one newer treatment targets intestinal immune tissue rather than the kidney.
Who is more likely to develop it
- Family history: relatives carry a higher risk, and several susceptibility genes are known, though no single gene causes it
- Ancestry: rates are highest in East Asia and lowest in people of African ancestry
- Sex: men are diagnosed more often than women in Western countries
- Age: onset clusters in adolescence and early adulthood, though diagnosis is possible at any age
- Other conditions: liver cirrhosis, celiac disease, inflammatory bowel disease, and some chronic infections can produce a secondary form
Nothing in a person’s diet, hydration habits, or exercise routine causes Berger’s disease. That point matters, because patients often arrive at their first nephrology appointment convinced they did something wrong. They did not. Lifestyle influences how fast Berger’s disease progresses, not whether it starts.
The lab tests that reveal Berger’s disease
No single blood test diagnoses Berger’s disease outright. Serum immunoglobulin A is raised in only a minority of patients, and a normal level rules nothing out. The diagnosis is built from a pattern across several urine and blood measurements, tracked over months rather than read once.
What urine testing shows
A standard urinalysis is the entry point for Berger’s disease. It detects blood invisible to the eye and estimates protein leakage. Under the microscope, two findings carry particular weight: red blood cells with distorted shapes, meaning they were damaged squeezing through inflamed filters rather than bleeding from the bladder, and cylindrical clumps molded inside the kidney tubules. A technician confirms these on a urine microscopy sample, and reports sometimes flag red blood cell casts as a signal of glomerular origin.
Quantifying protein comes next. A dipstick gives only a rough grade, so clinicians use a ratio that corrects for how dilute the sample is. Nephrologists most often track the urine albumin-to-creatinine ratio and its close relative the protein-to-creatinine ratio on a first-morning sample. Some centers still request a 24-hour urine protein collection, and follow-up visits re-check urine protein levels to see whether treatment is working.
What blood testing adds
Blood work measures consequences rather than cause. Laboratories report a serum creatinine value, a waste product that accumulates when filtration slows, and convert it into an estimated glomerular filtration rate, the number used to stage kidney function. Kidney panels also measure blood urea nitrogen, along with potassium, bicarbonate, and albumin. Antinuclear antibodies, complement levels, and hepatitis serology are ordered mainly to exclude other causes of glomerular inflammation.
| Test | What it looks at | Why it matters in Berger’s disease |
|---|---|---|
| Urinalysis with microscopy | Blood, protein, and cell shapes in a urine sample | Detects invisible bleeding and distinguishes kidney bleeding from bladder bleeding |
| Urine albumin-to-creatinine ratio | Albumin leakage corrected for urine concentration | The single best marker of risk and of treatment response over time |
| Urine protein-to-creatinine ratio | Total protein leakage on a spot sample | Used to set and follow treatment targets without a full-day collection |
| Serum creatinine | Muscle waste cleared by the kidneys | Rises as filtering capacity falls; the basis of the eGFR calculation |
| Estimated glomerular filtration rate | Calculated filtering capacity | Stages kidney function and tracks the slope of decline year to year |
| Blood pressure readings | Pressure inside the arteries | Both a consequence of kidney damage and a driver of further damage |
| Kidney biopsy | Actual kidney tissue under a microscope | The only way to confirm immunoglobulin A deposits and grade the damage |
How the diagnosis is confirmed
A kidney biopsy remains the only definitive test for Berger’s disease. Under local anesthetic, a specialist uses ultrasound guidance to take one or two thread-thin cores of tissue, usually as a day procedure. A pathologist applies a fluorescent stain that lights up immunoglobulin A in the mesangium. That glowing pattern is the diagnosis; everything before it is suspicion.
The biopsy also grades damage with a five-part score pathologists call MEST-C. In plain terms, it records how crowded the filter’s supporting cells are, how much inflammation sits inside the filter loops, how much scarring is present, and whether crescent-shaped areas of aggressive injury have formed. Two people with identical urine results can have very different scores, and the score shapes how aggressively treatment starts.
The international KDIGO guideline updated in 2025 encourages a more liberal approach to biopsy, since several effective treatments only become available once tissue confirms the diagnosis. Where a biopsy carries too much risk, for instance in people taking blood thinners, nephrologists may manage the case on the clinical pattern alone while monitoring closely.
Treatment options and what they aim to achieve
There is no cure for Berger’s disease, but the treatment goal is concrete: reduce protein leakage as far as possible and keep it there. The 2025 international guideline sets a target below 0.5 grams per day, ideally below 0.3 grams, alongside stable filtering capacity. Reaching it is strongly associated with preserved kidney function long term.
Foundational care for everyone
- An ACE inhibitor or angiotensin receptor blocker, prescribed even when blood pressure is normal, since these drugs lower pressure inside the filters and cut protein leakage
- Blood pressure control, generally toward a systolic reading near 120 mm Hg when tolerated
- An SGLT2 inhibitor, a class developed for diabetes that also protects kidney function in people without it
- Salt reduction, which makes blood pressure medication more effective
- Stopping smoking, managing weight, and treating high cholesterol where indicated
- Caution with regular anti-inflammatory painkillers
Many people with Berger’s disease who keep protein leakage low on this foundation alone need nothing further. Readers unfamiliar with the terminology often look up high blood pressure before their first nephrology visit.
Targeted treatment when protein leakage persists
When proteinuria stays above target despite full supportive care, nephrologists add disease-directed therapy. Systemic corticosteroids were long the default but carry real risks, including infection and bone loss, so their use is now more selective. Newer options act on specific steps of Berger’s disease instead: a capsule releasing budesonide in the part of the intestine where the abnormal antibody is produced, drugs blocking endothelin receptors to relieve pressure inside the filters, complement inhibitors that switch off one arm of the immune cascade, and antibodies neutralizing the signals that drive B cells to make faulty immunoglobulin A. Several reached the U.S. market in recent years, including an accelerated approval granted in July 2026.
If kidney function eventually fails, dialysis and transplantation both work well. Immunoglobulin A deposits can reappear in a transplanted kidney, so recipients continue urine monitoring afterward. Some people in this situation are also managing chronic kidney disease from more than one cause at once.
When to see a doctor
- Urine that turns pink, red, brown, or cola-colored, even once and painlessly
- Urine that stays foamy across several days
- New swelling of the ankles, hands, or face, particularly with rising weight
- A blood pressure reading that is newly high in someone under 40
- Reduced urine output, breathlessness, or persistent nausea
Living with Berger’s disease day to day
In Berger’s disease, monitoring replaces symptoms as the guide. Most people settle into checks every three to six months once stable, more often after a treatment change. Each visit typically pairs a urine protein measurement with creatinine, eGFR, and a blood pressure reading. The trend across several visits reveals far more than any single result: a mildly abnormal number that stays flat for years is very different from the same number climbing steadily.
Practical habits help. Moderate salt, regular activity, prompt treatment of throat and gut infections, and avoiding tobacco all reduce strain on the filters. Protein restriction is not routinely advised and can do harm without supervision. Pregnancy is usually possible but should be planned with a nephrologist, since some medications used in Berger’s disease are unsafe in pregnancy. People who track their own numbers often keep a log of a standard urine test panel alongside their blood pressure readings.
The outlook for Berger’s disease has genuinely improved. A generation ago, supportive care and steroids were the whole toolkit. Today someone with well-controlled protein leakage and normal filtering capacity has a realistic prospect of never needing dialysis, and the options keep expanding.
Latest scientific advances
The last three years have changed the treatment of Berger’s disease more than the previous thirty. Here is what the newest research found, and what it means if you or someone close to you lives with this diagnosis.
The treatment target moved lower
A 2025 review pooling twenty-three studies of more than fifteen thousand patients found that even modest protein leakage, at levels once considered acceptable, was linked to faster loss of kidney function. What this means for you: the aim is no longer simply to bring protein down, but to push it as low as treatment safely allows and keep it there. The 2025 international guideline reflects this with a stricter target and earlier biopsy.
A capsule that works in the gut, not the kidney
A two-year randomized trial, meaning participants were assigned by chance to the drug or a dummy capsule so the comparison stays fair, tested a budesonide capsule designed to release in the lower small intestine, where the faulty antibody is made. Protein leakage fell and kidney function held up better than with supportive care alone. What this means for you: treating gut immune tissue is now an accepted way to slow Berger’s disease, and it avoids many side effects of whole-body steroids.
Drugs that relieve pressure inside the filters
A large trial of atrasentan, which blocks a hormone that tightens blood vessels, showed a clear drop in protein leakage on top of standard therapy. What this means for you: this class offers a non-immune way to protect the filters, useful for people who cannot tolerate immune-suppressing drugs. Fluid retention is the side effect doctors watch for.
Switching off one arm of the immune system
Iptacopan blocks one step of the complement cascade, the part of the immune system that amplifies inflammation. The full two-year analysis published in 2026 reported that kidney function declined more slowly on the drug than on placebo. What this means for you: this is one of the first newer treatments with evidence on filtering capacity itself, not only on the protein number that stands in for it.
Antibodies aimed at the source of the faulty protein
Three phase 3 trials, the large-scale stage of testing before wide approval, reported interim results on drugs that neutralize the signals telling B cells to produce abnormal immunoglobulin A: sibeprenlimab and atacicept in 2025, telitacicept in 2026. All three cut protein leakage substantially. What this means for you: turning down production at the source, rather than mopping up damage, now has consistent support across independent trials in Berger’s disease. These are interim readouts, so the long-term effect on kidney survival still needs confirmation, and one of these drugs reached the U.S. market in 2026 under an accelerated pathway that requires further evidence to follow.
Comparing the options directly
A 2025 network analysis, a method that indirectly compares treatments never tested head to head, pooled fifty-seven trials across nineteen interventions. It reinforced that supportive care combined with a targeted drug outperforms either alone. What this means for you: no single treatment suits everyone, and the choice depends on biopsy findings, kidney function, and tolerance. Research continues in recruiting trials, including a phase 3 study of felzartamab opened in 2025.
All of this evidence comes from studies in adults with confirmed Berger’s disease and specific levels of protein leakage. It informs conversations with a nephrologist; it does not replace them.
Glossary
| Term | Definition |
|---|---|
| Glomerulus | One of the roughly one million microscopic filters inside each kidney. The plural is glomeruli. |
| Immunoglobulin A (IgA) | An antibody that normally defends the surfaces of the airways and gut. An abnormal form of it drives this disease. |
| Mesangium | The supporting tissue at the center of each kidney filter, where the immune complexes settle. |
| Hematuria | Blood in the urine. It can be visible to the eye or detectable only by laboratory testing. |
| Proteinuria | Protein leaking into the urine, a sign that the kidney filters are damaged. Foamy urine is the everyday clue. |
| Albumin-to-creatinine ratio (ACR) | A urine measurement that compares albumin to creatinine so results stay comparable regardless of how dilute the sample is. |
| Estimated glomerular filtration rate (eGFR) | A calculated figure showing how much blood the kidneys filter each minute. It is used to stage kidney function. |
| Kidney biopsy | A procedure taking a tiny sample of kidney tissue with a needle so a pathologist can examine it under a microscope. |
| MEST-C score | A five-part grading of what the biopsy shows, describing inflammation and scarring. It helps predict how the disease may progress. |
| Nephrotic syndrome | A pattern of very heavy protein loss with swelling and low blood albumin, seen in a minority of cases. |
Frequently asked questions
Is Berger’s disease an autoimmune condition?
It is immune-mediated, which is close to autoimmune but not identical. The body does not attack its own kidney tissue directly. Instead it produces antibodies against an abnormal form of its own immunoglobulin A, and the resulting complexes lodge in the kidney filters and cause inflammation there. The kidney is more of a bystander than a target. This distinction matters for treatment, because therapies now aim at where the faulty antibody is produced rather than broadly suppressing the immune system.
What is the life expectancy with this condition?
Most people diagnosed with this kidney disease live a normal lifespan. Outcomes depend heavily on how much protein the kidneys leak and whether filtering capacity stays stable. Someone with minimal protein loss and normal function at diagnosis, who keeps blood pressure controlled, often never progresses to kidney failure. Around a quarter of adults do eventually need dialysis or a transplant, usually after many years, and both treatments work well in this group. Because the range of outcomes is wide, personal numbers matter far more than general statistics.
Is it inherited from a parent?
Not in the way a single-gene condition is. Most cases occur in people with no affected relatives. That said, family clusters exist, and researchers have identified a number of genes that raise susceptibility. Having a parent or sibling with the disease modestly increases your own risk, which is reason enough to mention it to your doctor and to have your urine checked. Routine genetic testing is not part of standard care.
Can diet change the course of the disease?
Diet supports treatment but does not replace it. Reducing salt is the change with the clearest benefit, because it makes blood pressure medication work better and lowers protein leakage. A generally balanced eating pattern rich in vegetables and low in ultra-processed food helps blood pressure and cholesterol. Severe protein restriction is not routinely recommended and can cause harm without dietitian supervision. If kidney function declines, a dietitian may adjust potassium, phosphorus, or fluid intake based on your lab results.
Can it go away on its own?
Visible bleeding episodes resolve on their own within days, which often gives the impression that the problem has passed. The underlying process usually continues quietly. A minority of people, particularly children and those with minimal protein leakage, do enter long-lasting remission with no detectable abnormality. For most, the disease persists at a low level and needs periodic monitoring rather than active treatment. Stopping follow-up because you feel well is the most common avoidable mistake.
How often should kidney tests be repeated?
Once the situation is stable, most nephrologists repeat urine protein, creatinine, eGFR, and blood pressure every three to six months. Checks come closer together after a new diagnosis, after any change of medication, or if protein leakage rises. If everything has been unchanged for years and protein loss is minimal, annual checks may be enough. Your own schedule should come from the specialist following you, since it depends on your biopsy findings and current numbers.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases — IgA Nephropathy — NIDDK, National Institutes of Health niddk.nih.gov
- Mayo Clinic — IgA nephropathy (Berger disease): Symptoms and causes — Mayo Clinic mayoclinic.org
- Cleveland Clinic — IgA Nephropathy (Berger Disease): Symptoms and Treatment — Cleveland Clinic my.clevelandclinic.org
- Floege J, et al. — Executive summary of the KDIGO 2025 Clinical Practice Guideline for the Management of Immunoglobulin A Nephropathy and Immunoglobulin A Vasculitis — Kidney International, 2025 doi.org/10.1016/j.kint.2025.04.003
- Yamaguchi Y, et al. — The Association between Low-Grade Proteinuria and Adverse Kidney Outcomes in IgA Nephropathy: A Systematic Review and Meta-Analysis — Clinical Journal of the American Society of Nephrology, 2025 doi.org/10.2215/CJN.0000000952
- Lafayette R, et al. — Efficacy and safety of a targeted-release formulation of budesonide in patients with primary IgA nephropathy (NefIgArd): 2-year results from a randomised phase 3 trial — The Lancet, 2023 pubmed.ncbi.nlm.nih.gov/37591292
- Heerspink HJL, et al. — Atrasentan in Patients with IgA Nephropathy — New England Journal of Medicine, 2024 doi.org/10.1056/NEJMoa2409415
- Barratt J, et al. — Iptacopan in IgA Nephropathy: Final 24-Month Data — New England Journal of Medicine, 2026 doi.org/10.1056/NEJMoa2600743
- Perkovic V, et al. — Sibeprenlimab in IgA Nephropathy: Interim Analysis of a Phase 3 Trial — New England Journal of Medicine, 2025 doi.org/10.1056/NEJMoa2512133
- Lafayette R, et al. — A Phase 3 Trial of Atacicept in Patients with IgA Nephropathy — New England Journal of Medicine, 2025 doi.org/10.1056/NEJMoa2510198
- Lv J, et al. — Telitacicept for IgA Nephropathy: Interim Analysis of a Phase 3 Trial — New England Journal of Medicine, 2026 doi.org/10.1056/NEJMoa2514415
- Chen B, et al. — Efficacy and safety of agents for IgA nephropathy: a network meta-analysis of randomized controlled trials — Frontiers in Medicine, 2025 doi.org/10.3389/fmed.2025.1515723
- ClinicalTrials.gov — A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study of Felzartamab in Adults With IgA Nephropathy (PREVAIL), NCT06935357 — U.S. National Library of Medicine, 2025 clinicaltrials.gov/study/NCT06935357
- U.S. Food and Drug Administration — FDA Approves New Treatment to Reduce Proteinuria in Adults with Primary Immunoglobulin A Nephropathy — FDA, 2026 fda.gov
Further reading
- Readers comparing urine appearance with lab findings often consult a guide to urine color and test results.
- Anyone investigating back pain alongside blood in the urine should also read an overview of kidney stones.
- People whose blood work suggests a broader immune problem may want an explanation of lupus and its lab markers.
- Fever with flank pain points elsewhere, and many readers then review a summary of kidney infection symptoms.
- Those following early protein leakage will find it useful to read a page on microalbuminuria results.
Understand your lab results with BloodSense
Berger’s disease is followed almost entirely through numbers: how much blood and protein appear in the urine, what creatinine and eGFR show about filtering capacity, and whether those figures hold steady from one visit to the next. Lab reports rarely explain any of that in words a patient can use. BloodSense reads your urine and blood results and translates them into clear language, so you arrive at your appointment knowing which values changed and what to ask about. It helps you understand your results; it does not diagnose, and it does not replace your doctor.
