Differential diagnosis and chronic kidney disease (CKD)

Why is a differential diagnosis important if I have CKD? 

Many people with CKD don't know the cause. Some kidney diseases can look the same at first and are difficult to identify without further testing or biopsy, like IgA nephropathy or focal segmental glomerulosclerosis. A differential diagnosis helps doctors compare these conditions and figure out which one is causing your kidney problems. It also helps reduce errors in diagnosis because of the in-depth process that doctors follow.  

A differential diagnosis can provide other important information, including: 

Getting a differential diagnosis is not something that happens in a single visit. It is a step-by-step process where your doctor gathers information, considers different possibilities and rules things out over time. The approach may look different for each person depending on their symptoms, medical history and overall health.  

Your doctor will likely follow these steps: 

1. Ask about your symptoms: your doctor will ask you questions about what you are feeling, including when your symptoms started, how long they last and if anything makes them better or worse. 
2. Review your medical history: going through your medical history can include talking about any other health issues you have, medicines or supplements that you take, and lifestyle factors like your use of alcohol and/or tobacco, what you eat, and how active you are.
3. Perform a physical exam: your doctor will check your overall health by measuring things like height, weight, blood pressure, and temperature. They may also assess areas of your body to look for swelling, tenderness, or other signs that could point to a cause.
4. Create a list of potential conditions: based on your symptoms, medical history, and physical exam, your doctor will compile a list of conditions that could be the cause of your CKD. 
5. Additional testing: the information they've gathered, and the list of potential conditions will help your doctor decide what kind of tests and lab work you may need to help them narrow down the list. Learn more about kidney disease tests.
6. Update the list based on test results: over time, as more testing is done or new symptoms appear or change, your doctor will continue to update the list.  

Your doctor will repeat this process until a diagnosis can be made. If your doctor thinks that a rare disease may be the cause of your kidney disease, they may decide to refer you to a specialist.  

During this process, your doctor may also decide to start treatments (like starting new medicines) to help manage your symptoms and protect your kidney function. How your body responds to these treatments can give your doctor valuable information and help them refine the list of possible causes.

It can be frustrating if you hear your healthcare team talking about different conditions or telling you what they think you might have. Remember that this is a process, and the end goal for both you and your healthcare team is to understand what is causing your kidney disease.  

How can I help throughout the differential diagnosis process? 

Your role in the differential diagnosis process is important. While your doctor leads the medical work, the information you share and the way you stay involved can make a big difference. Being honest about your experiences and symptoms helps them better understand your condition and move closer to finding the cause of your kidney disease. 

Here are some ways to support your healthcare team:

• Be honest with them about your symptoms and what you are experiencing.
• Be open about your lifestyle, including what you eat, how much you exercise, how much alcohol you drink, if you use tobacco products, including smoking, chewing and vaping.
  • It may be uncomfortable to share some of these things, but the more detailed information you provide can be crucial to make sure your doctor accounts for all possible conditions.
• Bring a list of all prescriptions and over-the-counter medicines, vitamins, supplements, or herbal products you are using. 
• Keep track of your symptoms, including if they change, recur, or suddenly get better.
  • Try to note additional information, like what you were doing, where you were, and if you took any medicine around the time you noticed a change. 

This process can be long and frustrating but remember that it will help you find the cause of your kidney disease and hopefully get the best treatment possible.  

A differential diagnosis is just one step toward finding the exact cause of your symptoms. After your evaluation, your doctor may order more lab or imaging tests to confirm what's causing your kidney problems. Once the diagnosis is clear, your care team will explain your treatment options and next steps.