The CH50 blood test is ordered to measure the results of the body’s complement system. This system helps the immune system be able to remove pathogens that are invading the body. The complement system is made up of several proteins that are released by the liver and can be in such supply that they make up to 5% globulin fraction of a blood sample.
The CH50 blood test measures the results of the entire complement system instead of just parts of it, like other complement system blood tests are designed to do. It is most often ordered when there are recurrent infections occurring or an organism doesn’t seem to be getting purged by the immune system for some reason. It may also be ordered for these three additional reasons.
1. To confirm the diagnosis of the presence of a microbial infection.
2. To monitor the treatment and activity of a known autoimmune disease or disorder.
3. To track immune complex diseases or conditions, such as vasculitis or a kidney disorder known as glomerulonephritis.
The CH50 blood test will determine the presence of acute and chronic conditions. It is most often ordered when someone is experiencing inflammation that cannot be explained by any other reason during an exam. Someone with the symptoms of an autoimmune disorder may also have this test ordered for them.
No test preparation is generally needed for the CH50 blood test. It can be drawn from the arm on the same day it is ordered.
What Do the CH50 Blood Test Results Mean?
There complement activity levels that are measured may be classified as low, normal, or high. Normal results typically mean that there isn’t an underlying condition that is causing the inflammation or other symptoms a doctor may suspect could be complement system related. In rare instances, someone with a normally low CH50 result can have their results be normal because of a secondary cause that spikes complement system activity.
If the CH50 blood test results are low, the most common cause for this is malnutrition. There may also be a microbial infection present that is being inaccurately treated. Less common results from a low CH50 blood test would be an indication of liver cirrhosis, hepatitis, or serum sickness. Angioedema is also a possible reason for a low result.
High results on the CH50 blood test will occur when the immune system is actively engaged for some time with an underlying health issue. The most common reason for a high result is the presence of chronic inflammation. There are a few other reasons for this result if inflammation is not suspected, including ulcerative colitis, throiditis, juvenile RA, and certain cancers.
What Happens After the CH50 Blood Test?
Because the CH50 blood test is designed to take a look at the integrity of the complement system itself, it cannot be used to create a specific diagnosis. It will tell a doctor that the immune system has become engaged for some reason and will tell them that there is an underlying issue that needs to be treated in some way.
In most cases, the CH50 blood test results will return to normal after the underlying condition is addressed. For common issues, that means taking anti-inflammatory medication, antibiotics, or improving personal nutrition. In more complicated cases, the CH50 blood test may be used as one point of measurement for a treatment plan that has been implemented, but it is not a 100% definitive test.
The CH50 blood test may be ordered with other complement system tests to measure specific areas of the body. It is most commonly ordered in combination with C3 or C4 blood test. If a doctor has ordered a CH100 blood test, it is often this test that will be conducted.
What Are the Next Steps?
After examining the blood test, a doctor will often recommend a treatment plan based on the suspected diagnosis. For many patients, this means higher doses of medication, continued antibiotics, or lifestyle changes to prevent inflammation from being an ongoing issue.
If an autoimmune disorder is suspected from the results and a patient’s health history, then further testing may be ordered to determine the specific issue so that a proper treatment plan can be developed. For kids who are suspected of having juvenile RA, the CH50 blood test will often be enough to confirm the diagnosis.
Although some of the reasons why the CH50 blood test would come back as abnormal can be somewhat scary, most of the time it is used to confirm the presence of a treatable condition. If this test has been ordered for you, then be sure to ask your doctor questions about your overall health and what the results of this test mean for your unique health history.