Clinical Information

Interleukin-6 or IL-6 is a member of the cytokine family, with a pivotal role in the activation and regulation of immune response. Cytokines play several important roles, but its significance to the immune system has been given much importance recently: it triggers “inflammatory cascade” wherein a coordinated and sequential immune response is activated.

The Role of IL-6 in COVID-19 Patient Management

Some recent literature discussed the pathogenesis of cytokine release syndrome (CRS) in severe COVID-19 patients. CRS is a systemic inflammatory response that can be caused by infection, some drugs, and other factors, characterized by a sharp increase in pro-inflammatory cytokine level, like IL-6. Interleukin-6 is a key molecule in CRS and is now being tested to monitor its response in COVID patients. It can be used as predictor for a more immediate diagnosis of patients with higher risk of disease deterioration. Given the high levels of cytokines induced by SARS-CoV-2, a timely treatment to reduce lung damage via inflammation is critical to improving recovery rates and reducing mortality.

Other Clinical Applications of IL-6 Test

Evaluation of patients with:

• Suspected systemic infection
• Suspected localized infection, specifically prosthetic joint infection
• Suspected chronic inflammatory disorders, such as rheumatoid arthritis, systemic ankylosing spondylitis, or inflammatory bowel disease

Test Information

Analytical Method
The interleukin-6 (IL-6) cytokine assay employs an in vitro enzyme-linked immunosorbent assay for the quantitative measurement of human IL-6 in serum. This involves a sandwich immunoassay format where captured antibodies are coated in a single spot at the bottom of each well. The assay employs detection antibodies conjugated with chemiluminescent labels.

Interpretation
Elevated concentrations of Interleukin-6: >7 pg/ml may indicate an ongoing inflammatory response, which could be consistent with a systemic infection or chronic inflammatory disease. For COVID-19 diagnosis: serum IL-6 > 32.1 pg/mL is a severity predictor*

Caution

• Interleukin-6 (IL-6) is a non-specific marker associated with inflammatory response and is NOT diagnostic of any specific disease or disease process. Elevated concentrations of IL-6 must be interpreted within the clinical context of the patient.
• Normal concentrations of IL-6 DO NOT exclude the possibility of an ongoing inflammatory process.
• Results SHOULD NOT be used as a diagnostic procedure without confirmation from another medically-established diagnostic product or procedure.

Performance Characteristics

• Sensitivity: The minimum detectable dose of human IL-6 was determined to be at 3 pg/ml.
• Recovery: 92.63%
• reproducibility: RSD < 10%
• Specificity: This assay is specific to IL6 and will NOT detect other major cytokines.

Sample Information and Patient Preparation

• Specimen Required: 2 mL serum
• Turn-Around Time: Cut off every Monday 4PM, release by Thursday 12NN
• Patient Preparation and Collection:
  No patient preparation needed. Collect blood sample into 1 SST tube.
• Sample Storage:
  Store serum at -20°C until ready for shipping. Serum can be stored at refrigerated temperatures of 2 to 8oC for only 24 hours, after which must be frozen.
  Storage of serum at ambient temperature is NOT acceptable.
• Test Kit contains:
  1 SST Tube
  1 Plastic transfer pipette
  1 Amber microcentrifuge tube
  1 Sample collection guide