Inflammatory Cytokine Biomarker for Predicting
COVID Progression & Severity
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
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
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*
- 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.
- 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
- Standard Turn Around Time: 3 full days
- 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