Clinical viability of Fungitell, a new (1→3)-β-d-glucan measurement kit, for diagnosis of invasive fungal infection, and comparison with other kits available in Japan

Fungitell, a (1→3)-β-d-glucan (β-d-glucan) measurement kit, was approved in the United States in 2004. Three other kits for measurement of β-d-glucan, Fungitec G test MK (G-MK), β-Glucan test Wako (Wako), and β-Glucan test Maruha (Maruha), are commonly used for diagnosis of invasive fungal diseases in Japan. We evaluated the clinical viability of the Fungitell kit and compared it with the 3 kits generally used in Japan. The plasma β-d-glucan values measured with each kit showed some differences, possibly because different β-d-glucan standards, blood pretreatment methods, and kinds of horseshoe crab (a raw material for the main reagent) are used in each kit. Measures of diagnostic efficiency, for example the sensitivity, specificity, and positive and negative predictive values, varied among the kits. Although the areas under the receiver operating characteristic curves of the kits were not significantly different, the sensitivity of the Fungitell kit was the highest, followed by that of the G-MK kit. The sensitivity of the Wako and Maruha kits was low, but the specificity of these tests was higher than that of the G-MK or Fungitell kits. These inconsistent β-d-glucan measurements could interfere with diagnosis of invasive fungal infection. Early establishment of an international standard method for measurement of β-d-glucan is required.