Circulating immune complexes (CIC) Test

Doctors primarily order a CIC test to monitor disease progression in SLE patients. This test is also done to track the progress of other conditions like rheumatoid arthritis and certain kinds of tumours like acute leukaemia. Additionally, a CIC test is helpful in the detection of some types of allergies, inflammatory diseases and infections. Higher levels of CIC are often found during active phases of these diseases. 

However, this test does not specifically tell what kind of disease you have. It is only ordered when the doctor already knows you have a certain disease so the specific kind of CICs can be tracked. 

Generally, no special preparation is required for this test. If there is any specific requirement, your doctor will let you know before the test. Let your doctor know all your symptoms since the results of the test are interpreted in the specific context of your health history. Also, inform him/her if you are taking any medicines or supplements.

A blood sample is needed for this test. A laboratory technician or nurse will withdraw the required amount of blood from a vein in your arm and transfer it to a specialised container. 

There is usually no risk involved with this test. You may experience slight pain and bruising at the site of needle insertion; however, these symptoms will subside soon. If the bruising or pain persists, please consult your doctor.

Normal results:

The results of the CIC test are represented as two different values, one for C1q binding and the other for C3. 

For C1q binding: 

• Negative or normal: Less than 4.4 µg Eq/mL (microgram equivalents per millilitre)
• Open to further interpretation: 4.4-10.7 µg Eq/mL

For C3:

• Negative or normal: Less than 15.1 µg Eq/mL
• Open to further interpretation: 15.1-19.9 µg Eq/mL

If the test result is reported as negative or normal, it could mean that the immune complexes circulating in the blood sample are below the cut-off range for a disease condition. Although the result is reported as normal, the chances of an underlying condition cannot be completely ruled out with this test.

Since there are many methods available for this test and each method may give different values, the reference values mentioned here may differ from the values used by the laboratory where you get tested. The results are also open to various interpretations depending on your symptoms. Therefore, please speak to your doctor to understand what exactly your results mean for you.

Abnormal results:

Abnormal results in the CIC test are reported as positive. The values for a positive result are as follows: 

• For C1q binding: More than 10.7 µg Eq/mL
• For C3: More than 19.9 µg Eq/mL

Some conditions associated with elevated levels of CIC in the blood are:

• Kidney transplant
• Glomerulonephritis
• Rheumatoid arthritis
• SLE
• Scleroderma
• Vasculitis
• Ankylosing spondylitis
• Sjogren’s syndrome
• Lymphoma
• Hodgkin’s disease
• Leukaemia
• Bacterial infections (staphylococcal, streptococcal, pneumococcal, etc.) 
• Parasitic infections like malaria, Trypanosoma and toxoplasma
• Viral infections like hepatitis C, hepatitis B and HIV

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.