A 45-yrs-old woman has pain in her fingers on exposure to cold, arthralgias, and difficulty swallowing solid food. The most useful test to make a definitive diagnosis is

Ans. B. Anti Scl-70 antibodyThe symptoms of Raynaud's phenomenon, arthralgia, and dysphagia point toward the diagnosis of scleroderma.Scleroderma or systemic sclerosis is characterized by a systemic vasculopathy of small and medium-sized vessels, excessive collagen deposition in tissues, and an abnormal immune system. It is an uncommon multisystem disease affecting women more than men. There are two variants of scleroderma--a benign type called the CREST syndrome and a more severe diffuse disease. Anti-nucleolar anti-body occurs in only 20 to 30% of patients with the disease, but a positive test is highly specific. Cardiac involvement may occur, and an ECG could show heart block or pericardial involvement. Renal failure can develop insidiously Rheumatoid factor is nonspecific and present in 20% of patients with scleroderma.