Objectives: To detect P. jiroveci (previously named P. carinii) by PCR using FTA filter paper to extract the DNA, from noninvasive induced sputum samples of HIV/AIDS patients.
Material and Method: Fifty two HIV/AIDS patients suspected of Pneumocystis jiroveci pneumonia (PJP) in King Chulalongkorn Memorial Hospital were recruited. Both cytological method and PCR with FTA filter paper technique were performed to detect P. jiroveci from each specimen.
Results: The detectability rate of P. jiroveci infection was 21%. The PCR with FTA filter paper method was 4 folds much more sensitive than Giemsa staining technique. P. jiroveci was detected in 18% of the HIV/AIDS patients in spite of receiving standard PJP prophylaxis.
Conclusion: Detection of P. jiroveci by using FTA filter paper together with PCR in induced sputum samples could detect more cases of P. jiroveci infection than by using cytological method. DNA extraction using the FTA filter paper was more rapid and convenient than other extraction methods. The causes of failure of PJP prophylaxis should be evaluated.

Keywords: Pneumocystis jiroveci pneumonia, PJP, Polymerase chain reaction, FTA filter paper