Plasma beta-thromboglobulin in the differential diagnosis of Raynaud's phenomenon.

Plasma beta-thromboglobulin (beta TG) levels were measured by radioimmunoassay in 61 patients with systemic sclerosis, 19 with carefully defined primary Raynaud's phenomenon, and 8 with Raynaud's phenomenon in suspected transition to systemic sclerosis. Elevated beta TG was present in 50 (82%) patients with systemic sclerosis but levels could not be correlated with duration or extent of disease nor any particular pattern of visceral involvement. Transitional Raynaud's patients had elevated beta TG in 7 (88%) cases, whereas results in patients with primary Raynaud's phenomenon were comparable to normal controls. beta TG, a sensitive measure of in vivo platelet activation, is useful in the differential diagnosis of Raynaud's phenomenon.