A patient with AIDS is hospitalized with symptoms of high fever and rigidity of the neck. Routine laboratory tests on the CSF show a WBC count of 100/◊◊L with a predominance of lymphocytes and monocytes, the glucose of 55 mg/dL (plasma: 85 mg/dL), and a protein of 70 mg/dL. The Gram stain shows a questionable starburst pattern.

a. What additional microscopic examination should be performed?
b. If the test is positive, what is the patient’s diagnosis?
c. If the results of the test are questionable, what additional testing can be performed?
d. What could cause a false-positive reaction in this test?
e. If the tests named in a and c are negative, the glucose level is 35 mg/dL, and a pellicle is observed in the fluid, what additional testing should be performed?
f. If CSF and serum IEF were performed on this patient, what unusual findings might be present?