Correct!
3. Serum coccidiomycosis antibody
The patient is being seen in Minnesota and thoracic infections differ between the Southwest and the Midwest. In the Southwest, especially Arizona and Southern California, coccidioidomycosis (Valley Fever) is very common but she has no history of travel to the Southwest. In contrast, histoplasmosis is very uncommon in the Southwest but more common in the Midwest. Similarly, Legionella is more common in the Midwest. The Legionella urinary antigen test is a relatively inexpensive, rapid and specific test for L. pneumophila serogroup 1. However, it has a sensitivity of only about 70% and does not detect other serogroups. Influenza is common in both locales.
Her AFB smear, urine Legionella antigen, Blastomyces antibody, Cryptococcus antigen, and influenza PCR from nasopharynx swab were all negative. However, her urine histoplasma antigen was positive (> 39 mg/mL).
Which of the following are appropriate to do next?