Pe. Verweij et al., CLINICAL-EVALUATION AND REPRODUCIBILITY OF THE PASTOREX ASPERGILLUS ANTIGEN LATEX AGGLUTINATION-TEST FOR DIAGNOSING INVASIVE ASPERGILLOSIS, Journal of Clinical Pathology, 48(5), 1995, pp. 474-476
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.