Usefulness of ED036 kit for measuring serum PIVKA-II levels in small hepatocellular carcinoma

As a tumor marker for hepatocellular carcinoma (HCC), serum protein induced by vitamin K absence or antagonist-II (PIVKA-II) has high specificity, yet its sensitivity is relatively low, making it less suitable to serve as an adjunct in the diagnosis of small HCC. Recently, the ED036 kit (Eisai, Tokyo, Japan), whose detection limit is approximately ten times superior to that of a conventional kit (Eitest MONOP II, Eisai) has been developed. In this study, serum PIVKA-II levels in serum samples from 83 patients with benign chronic liver diseases (CLD) and 129 patients with HCC were measured with these two kits. With the ED036 kit, the cut-off value was set at 40 mAU/ml. For PIVKA-II measured with the ED036 kit, sensitivity was 45.0%, specificity 92.8%, and accuracy 63.7%, when we discriminated patients with HCC from those with CLD without HCC. While maintaining a high specificity, of 92.8%, the ED036 kit showed a significantly higher sensitivity than the conventional kit (45.0% versus 27.9%; P < 0.0001). With patients who had HCC consisting of a single nodule 30 mm or less in diameter, the positivity rate for serum PIVKA-II with the ED036 kit was significantly greater than the rate with the conventional kit (21.4% versus 9.5%; P < 0.005). Thus, the ED036 kit was thought to be more useful than the conventional kit as a tumor marker for small HCC.