▪Routine surveillance testing for serum CrAg is recommended for patients with CD4+ counts ≤ 100 cells/μL. A positive test should prompt evaluation for central nervous system infection.▪Prophylactic antifungals can reduce the frequency of primary disease, and in the United States, prophylaxis is recommended for those with a positive serum CrAg test. Here, CD4 is linked to central nervous system infectious disorder.