Test Details
Methodology
RA Factor: Immunoturbidimetry
CCP Antibodies: ELISA
14-3-3 eta protein: ELISA
Result Turnaround Time
8 - 12 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Aid in the diagnosis of rheumatoid arthritis (RA)1,2
Limitations
Results of this panel should be used in conjunction with clinical findings and other laboratory tests.
"It is acknowledged that an individual patient may meet the definition of RA without requiring that all tests be performed. For example, patients with a sufficient number of joints involved and longer duration of symptoms will meet criteria regardless of their serologic or acute-phase response status. The classification criteria can be applied to any patient or otherwise healthy individual, as long as 2 mandatory requirements are met: First, there must be evidence of currently active clinical synovitis (i.e., swelling) in at least 1 joint as determined by an expert assessor. Second, the criteria may be applied only to those patients in whom the observed synovitis is not better explained by another diagnosis."6
Footnotes
Custom Additional Information
This RheumAssure panel is comprised of three tests: RA Factor, CCP Antibodies, and 14-3-3 eta protein.
Used together, these three markers are able to diagnose established RA with a sensitivity of 88-96% and early RA with a sensitivity of 78- 92%.1,2
RA factor (also called RF) is elevated in established RA (sensitivity 72-85%)2,3 and in early RA (sensitivity 44-63%).1,4 Its specificity for RA is 80%.3
CCP Antibodies have similar sensitivities for established RA (66-79%) and early RA (59%)2,3 but higher specificity (90-96%).3,5
Serum 14-3-3 eta protein is elevated in both established RA (sensitivity 77%) and early RA (sensitivity 59-64%).1,2 It may provide a 15-20% incremental benefit in identifying early RA.1,4
Therefore, elevation of one or more markers of RheumAssure is consistent with a diagnosis of rheumatoid arthritis. When all three markers are negative, an RA diagnosis is less likely.
Specimen Requirements
Specimen
Serum
Volume
2 mL
Minimum Volume
0.8 mL
Container
Red-top or gel-barrier tube
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 3 days |
Refrigerated | 3 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
• RA Factor:<14 IU/mL
• CCP Antibodies IgG, IgA: Units
Negative: <20
Weak positive: 20 - 39
Moderate positive: 40 - 59
Strong positive: >59
• 14-3-3 eta protein: <0.2 ng/mL
Storage Instructions
Frozen preferred, refrigerate acceptable
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 504509 | RheumAssure | 504560 | Rheumatoid Arthritis Factor | Units/mL | 11572-5 | |
| 504509 | RheumAssure | 504554 | CCP Antibodies IgG/IgA | Units | 57093-7 | |
| 504509 | RheumAssure | 504551 | 14.3.3 ETA, Rheum. Arthritis | ng/mL | 75880-5 | |
| Order Code | 504509 | |||||
| Order Code Name | RheumAssure | |||||
| Order Loinc | ||||||
| Result Code | 504560 | |||||
| Result Code Name | Rheumatoid Arthritis Factor | |||||
| UofM | Units/mL | |||||
| Result LOINC | 11572-5 | |||||
| Order Code | 504509 | |||||
| Order Code Name | RheumAssure | |||||
| Order Loinc | ||||||
| Result Code | 504554 | |||||
| Result Code Name | CCP Antibodies IgG/IgA | |||||
| UofM | Units | |||||
| Result LOINC | 57093-7 | |||||
| Order Code | 504509 | |||||
| Order Code Name | RheumAssure | |||||
| Order Loinc | ||||||
| Result Code | 504551 | |||||
| Result Code Name | 14.3.3 ETA, Rheum. Arthritis | |||||
| UofM | ng/mL | |||||
| Result LOINC | 75880-5 |