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Test 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.


Secondary ID

624066

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, S

Specimen Type

Serum SST

Specimen 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

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