新しい血中前立腺特異抗原の測定法(IMx PA Dainapack)とその臨床的有用性に関する検討

Abstract

1)本法は再現性が安定し, 信頼度も高くかつ最小検出感度も高く(0.1ng/ml), その基礎的検討の結果は満足できる。2)日本人健常男性244例(21歳～79歳, 平均46歳)における測定の結果, 平均±S.D.は0.93±0.96ng/mlであった。正常上限を4.0ng/mlとしたとき98%(236/244)が4.0ng/ml以下であった。3)前立腺肥大症を対象として各カットオフ値における感度, 特異性, 正診率を求めたところ, カットオフ8.0ng/mlのとき最大正診率(感度84%, 特異性82%, 正診率83%)を示した。このことより正常と前立腺肥大症およびstage Aを含む早期前立腺癌との鑑別においては正常上限である4.0ng/mlを, 前立腺肥大症と前立腺癌との鑑別においては8.0ng/ml(stage Aの陽性率は66%から33%へ減る)をカットオフとすべきと考えられた

A study of the clinical utility of the IMx PA Dainapack, a new kit for detection of serum prostate specific antigen (PSA) by a fully automated enzyme immunoassay (EIA) system, was conducted. Results concerning reproducibility, dilution linearity and sensitivity were good. The excellent assay performance of this kit, particularly in terms of its high sensitivity (0.1 ng/ml), was confirmed. The upper limit of normal was determined to be 4.0 ng/ml from the mean +/- 3 S.D. (3.79 ng/ml) in healthy male controls (n = 244). Using 4.0 ng/ml as the upper limit of normal, 6 of 244 healthy male controls (2%) were positive. In various urinary diseases, 173 of 192 prostatic cancer (90%) and 46 of 112 benign prostatic hypertrophy (BPH) (41%) cases were positive. In prostatic cancer, the positive rates increased with the advance in clinical stage and in stage A the positive rate was especially high (8 of 12 (67%) were positive). On the other hand, using the BPH group as a negative control, the maximum accuracy rate for prostatic cancer had a cut-off value of 8.0 ng/ml. Thus, 8.0 ng/ml is an appropriate cut-off value differentiating prostatic cancer from BPH while 4.0 ng/ml is the cut-off value between the normal group and those with prostatic cancer (including stage A) and BPH. In the follow-up patients with prostatic cancer, serum PSA values measured by this kit reflected the effectiveness of treatment. The correlations between values obtained with the IMx PA Dainapack and 6 current kits were good (r = 0.93 to 0.99) but the values differed with the kit.(ABSTRACT TRUNCATED AT 250 WORDS)