The RPR test uses VDRL antigen containing fine: (A) Carbon paicles, (B) Iodine paicles, (C) Silver ions, (D) Sodium ions
Answer is A. The rapid plasma reagin (RPR) test is a macroscopic, nontreponemal flocculation card test used to screen for syphilis. RPR antigen is prepared from a modified VDR antigen suspension containing choline chloride to eliminate the need to heat inactivate serum, ethylenediaminetetraacetic acid (EDTA) to enhance the stability of the suspension, and finely divided charcoal paicles as a visualizing agent. Ref: Ananthanarayana textbook of Microbiology 9th edition Pgno : 374