a. Look at figure 17.9 b. What is the titer as shown?
In Figure

b. If the titer had been 40, would a different interpretation be made as to the immune status of the patient?
c. Which patients are positive in figure 17.10 b?
In Figure

d. What would it mean if a test 2 weeks later revealed a titer of 280?
e. What would it mean if no agglutination had occurred in any tube?

Transcribed Image Text:

The Tube Agglutination Test Unagglutinated cells t + Agglutinated cells Dilution 1/20 1/40 1/80 1/160 1/320 1/640 Control (no serum) I. in one method of setting up a double-diffusion test, wells are punctured in soft agar, and antibodies (Ab) and antigens (Ag) are added in a pattern. As the contents of the wells diffuse toward each other, a number of reactions can result, depending on whether antibodies meet and precipitate antigens. Side view Il Example of test pattern and results. Antigen (Ag) is placed in the center well and antibody (Ab) samples are placed in outer wells. The control contains known Abs to the test Ag. Note bands that form where Ab/Ag meet. The other wells (1, 2) contain unknown test sera. One is positive and the other is negative. Double bands indicate more than one antigen and antibody that can react. Test serum Ag Precipitation bands Test 2 IIl. Actual test results for detecting infection with the fungal pathogen Histoplasma. Numbers 1 and 4 are controls and 2, 3, 5, and 6 are patient test sera. Can you determine which patients have the infection and which do not? 6