Autoantibody Test Cost-Effective in Arthritis Diagnosis??

Autoantibody Test Cost-Effective in Arthritis Diagnosis

NEW YORK (Reuters Health) Oct 17 - Testing for autoantibodies against cyclic citrullinated peptide (aCCP) appears to be an economically feasible approach to early diagnosis of rheumatoid arthritis, and may even allow cost savings, German researchers report . more..

Anti CCP can diagnose rheumatoid arthritis even before clinical symptoms become apparent due to its high specificity for the disease. Similarly, IgM rheumatoid factor has occupied this role for decades before the discovery of anti CCP.

However, the controversy for a developing nation is whether anti CCP should be routinely implemented in our healthcare system. Is it as cost effective as believed.

Anti CCP is not without its drawbacks. There are incidences of false positives.

Positive anti-cyclic citrullinated proteins and rheumatoid factor during active lung tuberculosis.
Elkayam O; Segal R; Lidgi M; Caspi D
Ann Rheum Dis. 2006 Aug;65(8):1110-2. Epub 2005 Dec 16.

OBJECTIVES: To determine the prevalence of anti-cyclic citrullinated proteins (anti-CCP) and IgM rheumatoid factor (RF) in sera of patients with TB compared with healthy controls. PATIENTS AND METHODS: 47 consecutive patients with recently diagnosed active pulmonary TB and 39 healthy controls were studied. Data were collected by questionnaire on clinical features of the disease, duration of symptoms, fever, cough, arthralgia, myalgia, sicca symptoms. Serum samples were collected from patients before starting treatment for TB and frozen at -20 degrees C. Anti-CCP and IgM RF were evaluated by ELISA. RESULTS: The mean (SD) duration of TB related symptoms was 4.4 (1.7) months, 73% had fever, 94% a cough. Rheumatic symptoms were relatively rare: arthralgia (4%), myalgias (4%), eye and mouth dryness (2% and 9%, respectively). Mean (SD) levels of anti-CCP were significantly increased in patients with TB compared with controls: 44.9 (51) IU v 20 (7.3) IU (p = 0.002). Serum levels >40 U were found in 15/47 (32%) patients compared with 1/39 (2.6%) controls (p = 0.002). Mean (SD) serum levels of IgM RF were significantly increased in patients with TB: 17.8 (19) v 4.3 (5) (p<0.0001). IgM RF was positive (>6 IU) in 29/47 (62%) patients v 1/39 (2.6%) controls (p<0.0001). CONCLUSIONS: A significant proportion of patients with active TB have an increased titre of anti-CCP and IgM RF.

AD Department of Rheumatology, Tel Aviv Medical Centre, 6 Weizman Street, Tel Aviv 64239, Israel. oribe14@netvision.net.il

This study shows high false positives in active tuberculosis, a disease which is rather prevalent in Malaysia. Even other connective tissue diseases can give rise to a positive anti CCP.

My opinion is that the current role of anti CCP is to support a diagnosis of rheumatoid arthritis in cases where the diagnosis is difficult and uncertain. Combining both IgM RF and anti CCP improves the specificity of diagnosing the disease.

The consensus remains that rheumatoid arthritis should be diagnosed as early as possible and as aggressive as possible. Prognostication of disease with RF and anti CCP can lend credence to a more aggressive approach involving costly biologic agents.

In Malaysia, it can only be done at selective centers as many hospitals remain unmoved by this test. This test remains unavailable at UMMC. However, most private laboratories do offer this blood test.