[Evaluation of an improved pretreatment method for the measurement of (1-->3)-beta-D-glucan in blood samples].
Measurement of blood (1-->3)-beta-D-glucan is useful for early diagnosis and follow-up of the therapeutic process of deep seated mycoses. The Fungitec G test MK (Seikagaku Corp., Tokyo) kit using alkaline-pretreatment followed by chromogenic kinetic assay has been widely used in Japan because of its high sensitivity and easy handling of a large number of samples. Discrepancy in the levels of (1-->3)-beta-D-glucan and/or in the quantitative judgement, however, has been pointed out between this kit and other commercial kits. One of the reasons for this discrepancy has been reported to be non-specific reactions caused by substances other than beta-glucan. In this study, we have improved the alkaline pretreatment reagent by changing the concentration of KOH and salts, resulting in a marked reduction of the non-specific reaction. Recovery of standard beta-glucan added to plasma or serum after the improved pretreatment was 80 to 120%, and no amidolytic activity was detected either in plasma or in serum. By the improved pretreatment, the incidence of non-specific reactions, i.e., those that exceed the quantitation limit (3.9 pg/mL), were markedly decreased from 139 to 16 out of 200 plasma samples and from 106 to 22 out of 170 serum samples. The incidence of strong non-specific reactions, i.e., those that exceed the cut-off level (20 pg/mL), were also decreased from seven to one with plasma and seven to zero with serum samples. Correlation between corrected beta-glucan measurements by the current pretreatment and non-corrected ones by the improved pretreatment was quite good. The improved method is thus expected to decrease the frequency of non-specific false-positive reactions, with the high sensitivity of Fungitec G test MK.
Yoshida
Koichiro
K
Division of Respiratory Diseases, Department of Medicine, Kawasaki Medical School.
Niki
Yoshihito
Y
Matsuda
Junichi
J
Hirakata
Yoichi
Y
Oda
Toshio
T
Aketagawa
Jun
J
Obayashi
Taminori
T
Kohno
Shigeru
S
Oka
Mikio
M
D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D009181:Mycoses / Q000175:diagnosis*; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D047071:beta-Glucans / Q000097:blood*
D011933:Reagent Kits, Diagnostic; D047071:beta-Glucans