Serum and bal beta-d-glucan for the diagnosis of Pneumocystis pneumonia in HIV positive patients

D. Salernoe， D. Mushatt， L. Myers， Y. Zhuang， N. de la Rua， E.J. Calderon， D.A. Welsh

Background/purpose

The diagnosis of patients with pulmonary infiltrates and human immunodeficiency virus (HIV) infection remains a challenge. In current clinical practice the gold standard for Pneumocystis jirovecii pneumonia (PCP) diagnosis remains the identification of the organism in bronco alveolar lavage (BAL) using microscopy (e.g., silver stain). (1->3)-β -d-glucan (BG) is a polysaccharide that is present within the cell wall of Pneumocystis and other fungi.

Methods

We analyzed serum and BAL lavage fluid from a cohort of 119 patients that did have HIV, a diagnosis of pneumonia and underwent bronchoscopy (FOB) for diagnosis of PCP.

Results

The discriminative power of serum BG for the diagnosis of PCP in this group of patients was very high. Using a cutoff of 300 pg/mL, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 91%, 92%, 89% and 93% respectively. A model for ROC with just serum BG (N = 108) had an AUC of 0.95. Serum procalcitonin (PCT) and BAL BG were not as accurate for the diagnosis of PCP. For BAL BG using a cutoff of 783 pg/mL, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 72%, 79%, 72% and 79% respectively. The differences between the medians for serum PCT between the group with a without PCP did not reach statistical significance (p = 0.6137).

Conclusion

The measurement of serum BG should be incorporated in the diagnostic work up of HIV positive patients with dyspnea and infiltrates on chest X X-ray. Our study confirms the diagnostic value of serum BG previously reported by others but we add a cutoff value that we believe is more accurate for patients with AIDS and suspicion of PCP.

respiratory medicine

November 2014Volume 108, Issue 11, Pages 1688–1695

DOI: http://dx.doi.org/10.1016/j.rmed.2014.09.017 |