DIAGNOSTIC REAGENT

1457331 Diagnosing systematic lupus erythematosus AMERICAN CYANAMID CO 17 Sept 1974 [15 Oct 1973] 40537/76 Heading G1B A method for preparing a dry diagnostic reagent fixed on a microscope slide for the detection of human antinuclear factor in human serum or plasma in an immunofluorescent test for the diagnosis of systemic lupus erythematosus and other autoimmune diseases, comprises: (a) sieving only fetal calf thymus to obtain dispersed thymocyte cells therefrom; (b) suspending said dispersed thymocyte cells in isotonic buffered saline solution to a cell count of 1À0-1À5 x 106 cells/ml.; (c) placing at least one portion of about 0À05 ml. of said dispersed thymocyte cell suspension on a microscopic slide; (d) drying said amount of said dispersed thymocyte cell suspension on said slide; (e) fixing said dried cell suspension with modified Carnoy's solution; (f) washing said fixed suspension with water; (g) air drying said fixed and washed suspension; and (h) either placing said dried, fixed and washed slide in an air-tight container with dessicant or freezing said dried fixed and washed slide at a temperature of -20‹C or below and maintaining the frozen slide at a temperature of -20‹C or below. A test kit for detecting the diseases comprises at least one microscope slide having thereon three stabilized smears of the fetal calf serum thus prepared, a vial of positive sys- tematic lupus erythematosus (SLE) control serum obtained from SLE donors, a vial of negative systematic lupus erythematosus control serum obtained from non-SLE donors, and a vial of rabbit anti-human globulin, fluorescein conjugated. In practice, diluted serum is placed on one smear, and the positive and negative sera are placed on the other smears respectively; the slide is incubated, then washed and rinsed and diluted rabbit globulin is added to each to uniformly cover the smear, and the slide is again incubated, rinsed, washed, and spread with globuling and mounted for examination under a fluorescent microscope.