原　　　著

血小板数測定正確度向上のための
免疫学的血小板測定の検討

長　田　恵美里*1　猪　瀬　芳　子*2　武　内　　　恵*3
川　合　陽　子*4　渡　辺　清　明*5　　　　　　　　
　　　　　　　　　　　　　　　　　　　　　　
Implementation of the Immunological Method for
Improvement on Accurate Platelet Counts

Emiri OSADA*1, Yoshiko INOSE*2, Kei TAKEUCHI*3,
Yohko KAWAI, MD*4 and Kiyoaki WATANABE, MD*5

Rapid and accurate platelet counting is clinically required in severe thrombocytopenia. Prophylactic platelet transfusions are usually indicated in thrombocytopenia with platelet counts less than 20,000/μl. It was recently reported that the confidence lower limit of platelet counts by automated blood cell counter is about 14,000/μl. Clinical blood samples occasionally contain red-cell fragments or large platelets. In these cases, platelets should be counted by the phase-contrast microscopy. However, this manual operation is accurate but not precise and needs complicated technique. Abbott has developed an immunological platelet counting method by CELL-DYN 4000. We measured platelet counts in 137 blood samples from thrombocytopenic patients. These samples included red-cell fragmentation and large platelets on blood smears. We compared platelet counts with the immunological method(PLTimm) to those with Brecher-Cronkite, the optical(PLTo) and the impedance method(PLTi). PLTimm correlated more closely with the phase-contrast microscopy counts than PLTo or PLTi. In patients with microangiopathic hemolytic anemia, PLTo or PLTi could not exclude red-cell fragments, but PLTimm absolutely excluded red-cell fragments. In patients with giant platelets, PLTo or PLTi could not include large platelets but PLTimm included them and coincided well with platelet counts by the phase-contrast microscopy. These results indicate that the immunological method by CELL-DYN 4000 appears to be accurate and a very useful method for accurate platelet counts in severe thrombotybopenia.
[Rinsho Byori 50 : 887〜892, 2002]

*1Department of Laboratory Medicine, School of Medicine, Keio University, Shinjuku-ku, Tokyo 160-8582

【Key Words】platelet counts with immunological method(免疫学的血小板測定法)，CD61，red-cell fragment(破砕赤血球)，large platelet(大血小板)，CELL-DYN 4000

受付2002年2月15日・受理2002年8月13日
*1〜5慶應義塾大學医学部中央臨床検査部(〒160-8582 東京都新宿区信濃町35)

E-mail :emily@nisiq.net