Clinical Scenario. Step 1: Ask an answerable clinical question--P. I. C. O. Patient / Problem : Intervention / Exposure: Comparison: Outcome:. PICO. Question: Patient / Problem : Intervention / Exposure: Comparison: Outcome:.
Patient / Problem :
Intervention / Exposure:
Level of evidence:
Full spectrum of spectrum ? Yes□ No□ Unclear□
Randomly selected or consecutive patients ? Yes□ No□ Unclear□
評論Comment：1. 這個診斷試驗的研究對象足以代表所有病患群嗎?R - Was the diagnostic test evaluated in a Representative spectrum of patients ?
Both the index test and the reference standard carried out on all patients in the study ? Yes□ No□ Unclear□
Or follow-up people for an appropriate period of time ?Yes□ No□ Unclear□
評論Comment：2. 是否有一個當作確定診斷的參考標準試驗？A – Was the reference standard ascertained regardless of the index test result?
Was the reference standard appropriate ?Yes□ No□ Unclear□
The reference standard and the index test being assessed applied to each patient independently and blindly ?Yes□ No□ Unclear□
3.索引與參考標準之間是否有一個獨立、雙盲的比較？Mbo - Was there an independent, blind comparison between the index test and an appropriate reference ('gold') standard of diagnosis?
特異度(Specificity, Sp) = 無此病的人測出陰性結果的比率
陽性預測值(PPV) = 試驗陽性的人有此病的比率
陰性預測值(NPV) = 試驗陰性的人無此病的比率
Sn = a/a+c
Sp = d/b+d
PPV = a/a+b
NPV = d/c+d4.試驗的特徵是否有呈現出來？Are test characteristics presented ?
Can we generate a clinically sensible estimate of our patient’s pre-test probability (prevalence =a+c/a+b+c+d, from personal experience, prevalence statistics, practice databases, or primary studies)?
Are the study patients similar to our own?
Is it unlikely that the disease possibilities or probabilities have changed since this evidence was gathered?
Will the resulting post-test probabilities affect our management and help our patient?
Could it move us across a test-treatment threshold?
Would our patient be a willing partner in carrying it out?
Diagnostic test available, affordable, accurate, and precise in our setting?
The study patients similar to our own?
The disease possibilities or probabilities have changed since this evidence was gathered?
Pre-test probability (prevalence)= (a+c)/(a+b+c+d)
Post-test probability For LR+= a/(a+b) = PPV
Post-test probability For LR -= d/(c+d) - NPVC.研究結果能否應用到我們的病患? Can we apply this valid, important evidence about a diagnostic test in caring for our patient?