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Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation in the synovial membrane. Its more well-known symptoms are stiffness and swelling that can last for weeks, only to disappear and then return. These symptoms can happen in five or more joints. What some may not realize is that non-specific symptoms like fatigue, malaise, or depression can precede the characteristic symptoms by weeks or months, meaning patients may be unwell for quite some time.1-3
In later stages of the disease, joint deformity and progressive physical disability are common, but by then, the damage is irreversible.4 The goal, then, is to diagnose patients earlier so that better outcomes can be achieved. Early detection can potentially save patients from irreversible joint damage, systemic complications, and considerable morbidity–all of which they may face if their disease goes undiagnosed and untreated.1
Testing using a combination of serological assays and methods could play a significant role in the early diagnosis and treatment of RA, especially if the patient's clinical presentation is ambiguous.5 When the test result is positive, the positive predictive value (PPV) represents how likely it is that a patient has the disease given that the test result is positive.6 The PPV for RA approaches 100% when a patient exhibits positivity for a combination of markers Rheumatoid Factor (RF IgM), RF IgA, and a second-generation anti-Cyclic Citrullinated Peptide (CCP) IgG test.5 Testing for both anti-CCP and RF is beneficial when excluding the diagnosis of RA, rather than testing for either antibody alone.7
One of the most important and helpful tools in reaching a RA diagnosis is serological testing. Test results from one test alone give limited help in reaching a diagnosis. There are multiple blood tests that can be performed in the diagnostic process.7
International guidelines classification criteria recommend laboratory testing for:9
CCP antibodies appear in the early stages of rheumatoid disease, and RF of all isotypes (IgM and IgA) predate the onset of RA by several years.8 The detection of these isotypes, particularly IgA and IgM, have been found to be significant predictors of RA.9
If patients are exhibiting one or more common RA symptoms, test results can help provide a quicker diagnosis while ruling out other possible diseases. Research has shown definitive serological overlap between RA and systemic lupus erythematosus (SLE), known in combination as “rhupus,” Hashimoto’s disease, systemic sclerosis, and various connective tissue diseases (CTDs).10-13
Though RA is chronic and incurable, effective management can help reduce symptom flares and improve overall quality of life. Remission may even be possible if the disease is diagnosed and treated early.23