It seems that at least one of you caught the hint (major hint) about agglutination.
So far, I have liked the following:
“To determine whether the patients have serotype B, we can use agglutination tests.
I think that we would first prepare isolates from the patient samples and place these on slides. On one section (section #1) of each slide, we would add the serotype B specific antiserum. Our control would be on another section of the slide (section #2), and we would add normal saline to the sample in this section. a) A sample is serotype B positive if an agglutination reaction is visible on section #1 and not on section #2. b) If no agglutination reaction is visible on either section #1 or #2, then the sample is serotype B negative. c) If an agglutination reaction is visible on both section #1 and #2, then it is unclear whether the the sample is serotype B positive, since it may be a false positive. The experiment should likely be repeated, perhaps with fresh samples from the patient. d) If an agglutination reaction is visible on section #2 and not on section #1, the lab technique may have been faulty, and the experiment should likely be repeated. ”
I *loved* that there was a consideration here for controls – remember that every assay should have both positive and negative controls.
You all have a day or so left to chime in…I will post a link and a run through of how this can indeed work, but again I would rather here it from you 🙂