Serum Galactomannan and Diagnosis of Invasive Aspergillosis in Patients with Hematologic Malignancies, Blood and Marrow Transplantation

Abstract

Introduction: Invasive aspergillosis is a major cause of morbidity and mortality in hematologic malignant patients which have received intensive cytotoxic therapy or undergone blood and marrow transplantation (BMT). Early clinical and radiological diagnosis of IA is almost impossible and so mortality is very high. The main purpose of our study was to assay the diagnostic value of serum galactomannan (a fungal antigen found in the sera of infected patients) level in early diagnosis of invasive aspergillosis in patients with hematologic malignancies and BMT.
Method and materials: During 2009and2010, 70 adult patients with neutropenic fever of unknown origin in Shariati and Imam Khomeini centers of cancer and BMT were tested for galactomannan serum level on the 7^th day of fever or before starting antifungal treatment. The OD index of 0.5 or more was taken as positive result. Tissue biopsy from lung or sinus was performed in 8 patients and there were 7 positive results for aspergillus species. Galactomannan EIA test result was positive in 26 cases (37.1%). There were 7 cases of proven IA with positive tissue (lung or sinus) biopsy and 20 cases of probable IA. Overall, 27 cases were positive for IA (gold standard= proven IA+pobable IA).
Results: The study yields a sensitivity and specificity of 77.8% and 88.4% for this test, respectively. Positive and negative predictive value of the test with confidence interval of 95% was 80.8 % (60-92.7%) and 86.4 %( 72.0-94.3%), respectively.
Conclusion: Considering these results, galactomannan EIA test results must be interpreted cautiously as an alternative test to prove IA, and it doesn’t eliminate the need for other diagnostic criteria such as clinical symptoms, biopsy, imaging, etc. However, the test is substantially helpful in recognizing true cases of the disease.