PPD (purified protein derivative) or tuberculin is injected intradermally to test whether an individual is infected with tuberculosis. After 48-72 hours post-injection, the test is read by measuring:

A.The intensity of the red coloration of the injection site
B. The number of blebs or wheals at the injection site
C. The diameter of the bleb or wheal
D. The distance the bleb or wheal forms from the injection site


Answer: C. The diameter of the bleb or wheal

Biology & Microbiology

You might also like to view...

A skeleton has foramen magnum near the rear of the skull; this indicates the skeletal remains may be those of a

A. human. B. gorilla. C. dog. D. monkey. E. rat.

Biology & Microbiology

Which of the following is/are TRUE regarding the antidepressants?

a. Tricycles compound causes side effects due to lack of specificity against various transporters b. "MAO inhibitors" inhibits oxidation of NE (norepinephrine) and 5HT c. Lithium passes Na+ channel and interferes with adenylate cyclase d. all of above e. b and c

Biology & Microbiology

Closely linked genes nearly always end up

a. crossing over. b. assorting independently. c. in the same gamete. d. segregated during meiosis. e. inverted.

Biology & Microbiology

Chromatin consists of

a. DNA and histones. b. DNA, histones, and many other nonhistone proteins. c. mostly RNA and DNA. d. RNA, DNA, and nonhistone proteins. e. DNA only.

Biology & Microbiology