[Validation of a New (1 → 3)-β-D-Glucan Test Kit, Fungitec G Test MKⅡ " Nissui "]

Using 415 residual blood samples subjected to (1→3) -β-D-glucan assay, we studied the correlation of measurement results between Fungitec G Test MKII "Nissui" (Nissui Pharmaceutical Co., Ltd., Tokyo) and its predecessor, Fungitec G Test MK (Seikagaku Corporation, Tokyo), which is now out of production. Their major difference is that MK II uses reagents derived from blood cells of Limulus polyphemus, the American horseshoe crab, whereas MK used those of Tachypleus tridentatus, an Asian horseshoe crab. Passing-Bablok analysis showed a linear regression with nearly one-to-one correspondence (slope=1.065, intercept=-0.287) between the two test kits over the regular range of measurements (4.0 pg/ml -500 pg/ml ). This was also true when data were subdivided and analyzed in the low to medium (≦150 pg/ml ) and in the low range (≦50 pg/ml ). There were several cases, however, that showed a wide discrepancy between the pair of measurements. This discrepancy is believed to be due in part to the difference between Limulus and Tachypleus in their reactivity to β-glucans with diverse side chains. Despite of this, the even distribution on either side of the regression line of those samples that are associated with deep fungal infection and the abrupt disappearance of such samples below 20 pg/ml attest that MK II "Nissui" is an acceptable successor of MK.