17 In some laboratories onedimensional electroimmunoassay ma

17.    In some laboratories, one-dimensional electroimmunoassay may be used in addition to radial immunodiffusion. Which of the following is characteristic of electroimmunoassay?

         a.      it is a qualitative rather than quantitative test

         b.      it is performed in test tubes, like the Oudin test

         c.      lines of identity and nonidentity can be distinguished easily

         d.      antigen is moved by electrophoresis rather than diffusion

18.    A 22-year-old man is seen in a clinic with an ulcerative lesion on his penis. The diagnosis of primary syphilis in this patient can best be established by

         a.      FTA-ABS

         b.      testing for the presence of regain

         c.      culturing the organism from the penis

         d.      darkfield examination of material from the ulcer

19.   Two procedures, the VDRL and FTA-ABS, are used for screening and confirmation of syphilis because

         a.      the VDRL test is specific; the FTA-ABS test is sensitive

         b.      the VDRL test is sensitive, the FRA-ABS test is specific

         c.      both tests are highly sensitive

         d.      both tests are highly specific

20.    Which of the following statements is true regarding C-reactive protein (CRP)?

         a.      It is commonly elevated in patients suffering from bacterial infections

         b.      It disappears after an inflammatory process has subsided.

         c.      It can be elevated in postoperative patients.

         d.      It is diagnostic for active rheumatic fever.

21.    In rheumatic fever, damage to the heart appears to result from

         a.      streptococcal activation of forbidden clones

         b.      stimulation of delayed hypersensitivity response

         c.      antigenic similarity of myocardial tissue and group A streptococci

         d.      alteration of myocardial antigens by group A streptotocci

22.    The preferred procedure for measuring streptococcal antibodies formed during streptococcal pyoderma (streptococcal skin disease) is

         a.      anti-DNA

         b.      anti-DNase B

         c.      antirheumatoid factor

         d.      antistreptokinase

Solution

Question 17: Answer d. antigen is moved by electrophoresis rather than diffusion

Question 18: Answer c. culturing the organism from the penis

Question 19: Answer a. the VDRL test is specific; the FTA-ABS test is sensitive

Question 20: Answer a. It is commonly elevated in patients suffering from bacterial infections

Question 21: Answer d. alteration of myocardial antigens by group A streptotocci

Question 22: Answer b. anti-DNase B