CLINICAL-EVALUATION AND REPRODUCIBILITY OF THE PASTOREX ASPERGILLUS ANTIGEN LATEX AGGLUTINATION-TEST FOR DIAGNOSING INVASIVE ASPERGILLOSIS

Aims-The performance of the Pastorex Aspergillus antigen latex aggluti nation test for the detection of galactomannan in sera of patients at risk for invasive aspergillosis was evaluated, and the impact of stora ge on the reproducibility of the antigen titre was tested. Methods-Dur ing a one year period, 392 serum samples were obtained from 46 patient s at risk for invasive aspergillosis and tested for the presence of ga lactomannan using an Aspergillus latex agglutination test (Pastorex). Twenty three positive serum samples which had been stored at -20 degre es C for 2-16 months were retrospectively retested. Furthermore, two p ositive serum samples were stored at -20 degrees C and -70 degrees C a nd prospectively tested at three month intervals for a period of 15 mo nths. Results-The Pastorex Aspergillus test was positive in eight pati ents with microbiological, radiological, or histological evidence for invasive aspergillosis, but was negative in the initial serum sample f rom five of these patients. In two patients with histological evidence for invasive aspergillosis no positive reaction was found in six samp les. Six of 13 (45%) serum samples which had been stored at -20 degree s C for longer than six months had lost reactivity, while 0one of 10 ( 10%) samples had lost reactivity when stored up to six months. Two ser um samples which had been stored at -20 degrees C and -70 degrees C an d prospectively retested at three month intervals for 15 months, maint ained stable antigen titres. Conclusions-The Pasterex Aspergillus test is too insensitive to diagnose invasive aspergillosis in an early sta ge, but may contribute to the diagnosis when cultures remain negative and serial samples are obtained. To maintain a good reproducibility, s erum samples should be stored at -70 degrees C when the period of stor age exceeds six months.