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HelpTest Code 1433E 14-3-3 eta, Serum
Specimen Required
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL Serum
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Useful For
A potentially improved approach for the early identification of patients at-risk for or with early and established rheumatoid arthritis (RA) in combination with specific autoantibody tests
This test is intended to be used as an aid in the early diagnosis of RA and management of the disease.
Method Name
Enzyme-Linked Immunosorbent Assay (ELISA)
Reporting Name
14-3-3 eta, SSpecimen Type
Serum SSTSpecimen Minimum Volume
Serum: 0.4 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum SST | Refrigerated (preferred) | 14 days |
| Frozen | 100 days | |
| Ambient | 48 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Clinical Information
Serum 14-3-3 eta protein belongs to the 14-3-3 family of intracellular chaperone proteins (beta, gamma, epsilon, eta, sigma, theta, zeta). It is a joint-derived proinflammatory mediator that up-regulates cytokines and enzymes that perpetuate local and systemic inflammation and may contribute to joint damage.
Serum 14-3-3 eta is detectable at significantly higher levels in the serum from patients with rheumatoid arthritis (RA) when compared to healthy subjects and individuals with RA mimickers (other autoimmune conditions and viral/bacterial infections). It has also been reported as an important biomarker in diagnosing cases that are seronegative for traditional markers like rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA).
In addition to the contribution of 14-3-3 eta in the diagnosis of RA, previous studies have reported its clinical potential of 14-3-3 eta as a predictor of poor clinical and radiographic outcomes, both at baseline and after initiation of treatment, even in Simplified Disease Activity Index (SDAI) remitters. These studies suggest that 14-3-3 eta, c-reactive protein, age, and ACPA represent independent predictors of subsequent joint damage.
Reference Values
< 0.19 ng/mL
Interpretation
Serum 14-3-3 eta was tested in a clinically characterized rheumatoid arthritis (RA) and early RA patient Mayo Clinic patient cohort, where 275 of 446 patients (82.6%) were seropositive (defined as having 3rd generation anti-CCP IgG antibody [CCP3] >20 U and/or rheumatoid factor [RF] >14 IU/mL). A 14-3-3 eta cutoff of ≥0.19 ng/mL for both early and established RA patients was used to calculate the sensitivity and specificity of 14-3-3 eta for RA (n=113) and early RA (n=95).
Serum 14-3-3 eta slightly increased sensitivity for RA (87.0%) and early RA (75.8%) when used in concert with anti-CCP3 IgG and RF, versus the use of a combination of anti-CCP3 IgG and RF alone (RA sensitivity 82.6%, and early RA sensitivity 74.7%).
The addition of 14-3-3 eta offers an increase in specificity for RA (99.1%), and early RA (99.1%), relative to observed positivity with RF and anti-CCP3 IgG antibodies without the use of 14-3-3 eta (RA specificity 94.7%, and early RA specificity 94.7%).
|
Serum 14-3-3 eta concentration (ng/mL) |
Qualitative Interpretation |
|
<0.19 |
Negative |
|
≥0.19-0.39 |
Mild positive |
|
≥0.40-0.79 |
Moderate positive |
|
≥0.80 |
Strong positive |
Cautions
A test result that is inconsistent with the clinical picture and patient history should be interpreted with caution.
In rare cases, some individuals can develop antibodies to mouse or other animal antibodies (often referred to as human anti-mouse antibodies or heterophile antibodies) that may cause interference in some immunoassays. Caution should be used in interpretation of results, and the laboratory should be alerted if the result does not correlate with the clinical presentation.
Method Description
The JOINTstat 14-3-3 eta enzyme-linked immunosorbent assay is an immunoassay that uses a microtiter plate coated with a murine monoclonal antibody specific for human 14-3-3 eta, a horseradish peroxidase (HRP)-conjugated monoclonal antibody, and a chromogenic substrate. When standards, diluted controls, and diluted patient specimens are added to the coated wells, any 14-3-3 eta present binds to the immobilized antibody. After an incubation period, the wells are washed to remove material that did not bind. An HRP-conjugated anti-14-3-3 eta antibody is then added. This conjugate binds to the captured 14-3-3 eta, forming a detectable complex. Following incubation, another wash cycle removes unbound conjugate. A chromogenic substrate is introduced, and the HRP enzyme converts the substrate into a colored product that initially appears blue. When the reaction is stopped, the color changes to yellow. The absorbance at 450 nm is measured and is proportional to the concentration of 14-3-3 eta present in the standards, controls, and patient samples.(Unpublished Mayo method)
Day(s) Performed
Wednesday
Report Available
3 to 9 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
83520
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| 1433E | 14-3-3 eta, S | 75880-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 624066 | 14-3-3 eta, S | 75880-5 |