Interleukin 6 (IL6) Test

Interleukin-6 (IL-6) is a multifunctional cytokine that has a wide range of immunological actions. This cytokine is known for its high ability to initiate the acute phase response in the host defence mechanism. These cytokines help direct the body's immune response to infection, trauma, injury, etc. They're part of the "inflammatory cascade," which entails coordinated and sequential activation.

The development of several diseases, including diabetes, rheumatoid arthritis and cancer, has been linked to the overexpression of this cytokine.

IL-6 is an immune protein and a pyrogen. Our body produces IL-6 in response to an inflammatory condition. In both acute and chronic inflammatory conditions, interleukins are produced whether it is an infectious, non-infectious or autoimmune disease.

Inflammatory situations such as trauma, burns, infection and malignancies all trigger the production of IL 6.

Interleukin-6 binds to the IL-6 receptor alpha, causing transcription of inflammatory cellular products to begin. This cytokine has been linked to several chronic inflammatory diseases such as type 2 diabetes, juvenile rheumatoid arthritis and systemic lupus erythematosus.

IL-6 is also essential for the generation of blood cells, including white, red and platelets. IL-6 appears to have a significant role in the progression of Kaposi's sarcoma and multiple myeloma.

The IL-6 test is useful as a marker of immune system activation because it helps maintain immune responses. Inflammatory disorders, infectious diseases, autoimmune disorders, cardiovascular illnesses and some carcinomas can all cause an increase in IL-6. IL6 is an important early marker to detect cytokine storm in Covid 19 infected individuals(a marker to detect severity, hence, to decide if a patient needs hospital admission). The Interleukin test determines how much IL-6 is present in the blood sample.

Sepsis, Rheumatoid arthritis, systemic lupus erythematosus, diabetes, stroke, cardiovascular diseases

The IL-6 Test detects elevated interleukin-6 levels in the blood. It measures the exact value of interleukins in blood samples.

There is an elevation in IL-6 levels before the onset of acute and chronic inflammatory conditions. It guides doctors about the severity of inflammation. IL-6 helps in understanding the prognosis of the disease.

The IL-6 test detects elevated IL-6 levels in the blood. The muscles produce and secrete IL-6 in reaction to any inflammation in the body.

There is an elevation in IL-6 levels before the onset of acute inflammatory conditions.

IL-6 Test is suggested in people presenting with acute inflammatory signs such as:

• High fever
• Increased heart rate
• Excessive sweating
• Breathlessness
• Sudden rash or hives on the skin
• Swollen mouth or tongue
• Swollen or rashes on lips
• Dizziness
• Severe body pain
• Muscle soreness

Interleukin-6 Test is suggested in people with chronic inflammatory signs such as:

• Pain
• Frequent exhaustion
• Muscle stiffness and soreness
• Low-grade fever
• Chills with or without fever
• Frequent headaches
• Nausea and indigestion
• Sleeplessness or insomnia
• Unexplained weight loss
• Obesity
• Joint stiffness

If the doctor suspects any of the above conditions, he may ask for an IL-6 test. This test also detects the severity of inflammatory disorders. Doctors also suggest IL-6 tests to monitor the line of treatment for the above-listed diseases.

IL-6 in the blood decreases with a decrease in inflammation.

Some disease conditions for which the IL-6 test is prescribed are:

• Covid SARS infection
• Uncontrolled diabetes
• Sepsis
• Cancer
• Infection caused by bacteria or viruses
• Rheumatoid arthritis
• Atherosclerosis
• Irritable bowel syndrome
• Tissue injury
• Autoimmune diseases

The IL-6 test applies to males and females, both adults and children. Some medicines like nonsteroidal anti-inflammatory drugs, sleeplessness and obesity may give false elevations in IL-6 levels.

The qualitative IL-6 Test determines the severity of inflammation.

In acute inflammatory conditions, quantitative IL-6 repetition helps to assess prognosis.

Within two to four hours of any inflammatory process, IL-6 levels begin to rise. After 24 hours, IL-6 values start falling if there is recovery and healing. If IL-6 doesn't reduce within this duration, the IL-6 test is repeated. If IL-6 levels keep increasing, then doctors advise repeating it every day.

In Covid 19 infected patients Doctors may ask for IL-6 levels and if its levels are high IL-6 level repetition on alternative days or twice a week till IL-6 values show a gradual decrease. A repetition of tests continues till their value falls within normal limits.

Before the Test

Before undergoing the Interleukin-6 Test, it is unlikely that your doctor will require you to take any special precautions. However, if you are to take this test with another one that requires special preparation, your doctor may suggest fasting for a specific time. Always speak with your doctor before a test.

During the Test

For the Interleukin-6 test, the phlebotomist will take a blood sample from your arm. Here's what will happen during the test:

• The likely puncture site will be sterilised with antiseptic.
• A tourniquet will be secured around your arm to make your veins stand out.
• A needle will be inserted into a chosen vein to draw the blood. This may cause a brief pinch for a few seconds.
• The blood will be collected in a vial/small test tube, and a label will be affixed with your details.

After the Test

Following the blood collection:

• A bandage will be placed over the insertion site to stem any bleeding.
• Bruising can happen. If you feel lightheaded (an uncommon side effect), you may be advised to rest for a few minutes.
• In case of persistent bleeding, pain, or rashes at the puncture site, contact your doctor.

The IL-6 test includes parameters of normal or elevated levels of interleukin-6. Interleukin Test results can be in terms of positive or negative.

Positive results mean higher levels of IL-6 and negative results indicate lower levels of IL-6.

Interleukin is the only parameter included in the IL-6 test. These values give an idea about the inflammatory response of the body. IL-6 Test value guides about what could be the underlying cause. IL-6 levels indicate the presence of infection or injury.

IL-6 levels monitor the treatment of infections like:

• To detect and manage cytokine storm in Covid 19 infected patients
• If there is no inflammation in the body, the values will be within normal limits.
• If the body is fighting infection or recovering from trauma, values of IL-6 will be higher.
• In acute conditions, weak defence and low recovery rate IL-6 values will be abnormally high.

The normal range is 0– 16.4 pg/mL for IL-6.

Interleukin-6 (IL-6) is a nonspecific inflammatory response marker. It does not diagnose any disease or disease process. Elevated IL-6 concentrations interpretation must be in the context of the patient's clinical history.

The normal values and reference ranges of the test may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

Interleukin-6 (IL-6) concentrations that are higher may indicate an active inflammatory response. IL-6 plays a vital role in cellular homeostasis under normal circumstances.

Increased or abnormal levels of IL-6 seen in these diseased conditions:

• Diabetes - There is a long-standing connection between inflammation and diabetes. IL-6 is raised in people with insulin resistance, along with other inflammatory markers.
• Sepsis and Septicemia - Interleukins acts as a mediator during the acute phase of immune response to its inflammatory and clinical phase. In systemic septicemia like covid, interleukins reach high levels along with C reactive proteins.
• Autoimmune diseases - Autoimmune diseases like rheumatoid arthritis, ankylosing spondylitis and SLE show increases in interleukins. In these conditions, antibodies cause joint destruction and IL-6 is a crucial effector of this destruction. Although the cause is unknown, cytokines such as IL-6 are found in high concentrations in the arthritic joints, blood and synovium of persons who have it.
• Carcinoma - Carcinomas like multiple myeloma, the bone marrow produces interleukins. For cancer to initiate, factors like altered growth signals, lack of response growth-inhibiting signals, failure to abnormal cell destruction and uncontrolled multiplication are root causes.
• Inflammatory conditions - Inflammatory conditions such as prosthetic joint infection, periodontitis and osteomyelitis show a systemic response to local infection. The symptoms of fever, leukocytosis and chills are expressed as a systemic response to severe infection. IL-6 is one of the most important proinflammatory cytokines in producing fever and it is responsible for inducing the acute phase response.

Overall, the IL-6 cytokine is a nonspecific biomarker of systemic inflammation that, under the right circumstances, could be helpful in clinical decision-making.