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Rheumatoid Arthritis (RA) Expanded Profile
C-Reactive protein, quantitative; cyclic citrullinated peptide antibodies, IgA, IgG; rheumatoid arthritis factor; sedimentation rate (modified Westergren)
According to the American College of Rheumatology 2010 Classification Criteria for Rheumatoid Arthritis, "measurements of Rheumatoid Arthritis Factor (RF), anti-CCP, ESR, and CRP are included as a part of the diagnostic algorithm. To classify a patient as having or not having definite RA, a history of symptom duration, a thorough joint evaluation, and at least 1 serologic test (RF or anti-CCP) and 1 acute-phase response measure (ESR or CRP) must be obtained."1
Markedly lipemic or contaminated specimens may yield false-positive results. CRP arises as a nonspecific response to tissue injury and inflammation. The ESR is of limited diagnostic value in severe anemia or in hematologic states that affect increased size and shape variation (poikilocytosis) of the RBC (ie, presence of sickle cells or spherocytes). Extreme plasma viscosity will result in a decreased ESR.
CRP: Latex immunoturbidimetry; CCP: Enzyme-linked immunosorbent assay; RA Factor: Latex immunoturbidimetry; Sedimentation Rate: Automated and manual methods
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"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."1
Serum and whole blood
Whole blood: 2 mL and serum: 1.5 mL
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Refrigerate. Serum is stable for seven days at room temperature, refrigerated, or frozen for 14 days. Freeze/thaw cycles: stable x3. Whole blood: 24 hours
Causes for Rejection
Hemolysis; lipemia; clotted, underfilled tube; specimen older than 24 hours, improper labeling, transport tubes with whole blood, specimen received in any anticoagulant other than EDTA; specimen diluted or contaminated with IV fluid; patient specimen with presence of cold agglutinins or cryoglobulins; specimen received with plasma removed
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|164245||RA Expanded Profile||006171||RA Latex Turbid.||IU/mL||11572-5|
|164245||RA Expanded Profile||006627||C-Reactive Protein, Quant||mg/L||1988-5|
|164245||RA Expanded Profile||164915||CCP Antibodies IgG/IgA||units||57093-7|
|164245||RA Expanded Profile||005215||Sedimentation Rate-Westergren||mm/hr||4537-7|