Interference of (1 --> 3)-beta-D-glucan administration in the measurement of plasma (1 --> 3)-beta-D-glucan

Blood (1 --> 3)-beta-D-glucan (betaG) measurement is widely used as an effective sero-diagnostic method for deep-seated mycosis. Antitumor betaG (lentinan, schizophyllan) administration is known as one of the false-positive factors of blood betaG measurement. To understand the influence of administered betaG preparation to betaG measurement in blood, we compared the interfering effect of betaG administration in different betaG measuring methods.

betaG concentration in plasma was measured by three different methods.

betaG concentration was measured in plasma of 18 samples of 7 cases with betaG administration and 86 samples without betaG administration. The period after last betaG administration was three days to three years.

In the cases for which betaG was administered, blood betaG level drastically increased using the method which employs alkaline pretreatment. Even in the cases for which betaG was administered three years previously; betaG value measured by alkaline pretreatment was significantly high. Thus, interference of betaG administration in blood betaG measurement continued for years after the last administration.

Disparity in betaG values measured by different methods for betaG administered cases is due to differences among sample pretreatment methods. Conformation of administered betaG seemed to be transformed into a sensitive form to factor G by alkaline pretreatment. Especially in the case of the alkaline pretreatment method, betaG administration disturbance was much stronger than for dilution-heating pretreatment. Therefore, in suspected cases, it is important to pay attention to betaG administration during the previous few years.