摘要
本文针对文献中关于似然比非常稳定,比灵敏度(Se)和特异变(Sp)更稳定这一观点分析了诊断试验中似然比L与灵敏度Se、特异度Sp的关系。结果表明:①Se与阳性似然比L+呈正比,与阴性似然比L-呈反比。②L+随Sp增大呈指数增大,增幅渐大,L-随Sp增大呈指数降低,降幅渐小;③当Se+Sp=1时,L+=L-=1;当Se+Sp<1时,Se对L+的影响大于Sp,而Sp对L-的影响大于Se;当Se+Sp≥1时,Sp对L+的影响大于Se,而Se对L-的影响大于Sp。因此似然比并不比,也不可能比灵敏度和特异度更稳定。此外指出似然比的固有缺陷并分析提出了高似然比对诊断试验灵敏度、特异度改变所需满足的条件。
The relationship between likelihood(L) and sensitivity, specificity (Sp) in diagnostic test was analysed in accordance with the viewpoint that the Se and Sp are more stable than L. The results showed that: (1)Se is directly proportional to positive likelihood (L +) , but inverse to negative likelihood (L-) ;(2)L+ increases as index form with Sp increasing, and the increment tend to become large; L - decreases as index form with Sp decreasing, and the decrement tend to become small;(3)if Se + Sp = l ,L+ =L- = 1 ;if Se+Sp<l, the effect to L+ for Se is stronger than that for Sp, and the effect to L-for Sp is stronger than that for Se, but the effect to L- for Se is stronger than that for Sp. Therefor L is not more stable than Se and Sp. Besides these, the intrinsic defect of L were pointed out and the prerequisite for the change of Se and Sp in diagnostic test to suit high value likelihood was analysed and put forward.
出处
《数理医药学杂志》
1995年第3期226-229,共4页
Journal of Mathematical Medicine
基金
国家自然科学基金资助项目
关键词
诊断试验
似然比
灵敏度
特异度
Diagnostic Test Sensitivity Specificity Likelihood
