Important tests for monitoring IgAN

Immunoglobulin A nephropathy (IgAN) is a rare disorder that causes damage to the kidneys, a pair of organs that act as filters for the blood.

IgAN causes clumps of immunoglobulin A (IgA) proteins to build up in the kidneys. This results in inflammation and damage to the kidneys. It is an “immune-mediated disease,” meaning the underlying causes are problems with the immune system.

More specifically, IgAN is related to abnormal activity within the complement system, a part of the immune system that activates proteins to heal injuries and fight infections. However, the causes of the disease are not fully understood, and the majority of cases have no identifiable cause.

Some cases develop as a result of other conditions, such as liver disease. This is referred to as secondary IgAN.

Important tests for monitoring IgAN

There is no cure for IgAN, but the disorder can be managed with treatment. Treatment options for IgAN are expanding, with new therapies that have become available in recent years, and other therapies that are in development. There are also steps a person with IgAN should take to keep their kidneys as healthy as possible.

Treatment of IgAN will include tests to monitor for kidney function and other health issues. These can include:

• Urinalysis. This is a urine test that measures the amount of protein, albumin (a type of protein), and blood in the urine. Normally these substances are not found in the urine or are found in minuscule amounts.
• Bloodwork. Your healthcare team may also order bloodwork to check levels of creatinine in the blood. Creatinine is a waste product created when the body digests proteins.
• Glomerular filtration rate (GFR), a measurement of how much blood the kidneys are filtering per hour. Most often this is measured with what is called an estimated GFR. Estimated GFR is calculated by measuring the amount of creatinine in the blood and/or urine.
• Blood pressure, a measurement on the force that blood exerts on the walls of blood vessels as it moves through the body. This is measured with a blood pressure cuff.
• Cholesterol test. Also called a lipid panel, this is a blood test that measures cholesterols and other fats circulating in the blood. Elevated levels contribute to cardiovascular disease and other health problems.

These tests are often used to monitor IgAN and measure how the condition is responding to treatment. Your healthcare provider will be your best source of information about your test results and what they mean.

Blood glucose

For people with IgAN (and other forms of kidney disease) an additional number to pay attention to is blood glucose. Also known as blood sugar, glucose is the body’s main source of energy. Levels that are too high (hyperglycemia) are a symptom of diabetes and prediabetes. Blood glucose levels can be measured using a variety of blood tests. Prolonged high blood glucose can damage blood vessels, including blood vessels in the kidneys.

What do these numbers mean for treatment?

High blood pressure and unhealthy cholesterol numbers are potential complications of IgAN, and these are associated with worse outcomes in people with IgAN. An important part of treatment is controlling these numbers.

You and your healthcare providers should also discuss your blood glucose numbers. Hyperglycemia is a potential side effect of corticosteroid medications, and courses of corticosteroid medications are a common treatment for IgAN. Potential side effects are an important topic to discuss before starting any treatment.

There are also several medications available specifically to treat IgAN, including medications that reduce proteinuria and medications that act on the complement system.

Changes to diet, including lowering sodium intake, are also recommended—and are another important topic to discuss with a healthcare provider.

Treatment can help slow the progression of kidney damage and prevent complications related to kidney damage.