Polymerase chain reaction on blood for the diagnosis of invasive pulmonary aspergillosis in cancer patients.

BACKGROUND

The premortem diagnosis of invasive pulmonary aspergillosis (IPA) is difficult to make and often missed. Several retrospective studies have suggested that Aspergillus polymerase chain reaction (PCR) performed on serum or whole blood is useful in diagnosing IPA. Two prospective studies confirmed this finding but included a small number of IPA cases.

METHODS

The current study was performed to determine the diagnostic role of Aspergillus PCR performed on whole blood specimens from 54 patients with cancer and pulmonary infiltrates for which bronchoscopy with fungal stains and cultures were performed. PCR through amplified Aspergillus mitochondrial DNA and alkaline protease genes was performed on whole blood samples.

RESULTS

The cohort in the current study was comprised of 4 patients with definite IPA, 7 patients with probable IPA, 7 patients with possible IPA, and 36 control patients with no evidence of IPA. The sensitivity, specificity, and positive and negative predictive values all were 100% for definite IPA cases and 57%, 100%, 100%, and 92%, respectively, for each of the probable and possible IPA cases.

CONCLUSIONS

Aspergillus PCR on whole blood samples is highly sensitive for the detection of IPA and is predictive for IPA. The sensitivity appears to be correlated with the certainty of diagnosis as proven by tissue invasion.