Page 41 - ESHRE2019

Reference standard Pos Neg
Studied Pos
test
Likelihood ratio for a positive test LH+ = S / (1 – Sp)
LH+ = 5.8
Odds of disease
= prevalence * (1 – prevalence) = 0.30 * (1 – 0.30)
= 0.43
Odds of the disease if test positive = Odds of disease * LH+
= 0.43 * 5.8
= 2.5
Neg
Statistical analyses
25
10
5
60
Sensitivity Specificity
S=25/30 (83%)
Sp=60/70 (86%)
Reference standard Pos Neg
Studied Pos
test
Likelihood ratio for a negative test LH- = Sp / (1 – S)
LH- = 5.1
Odds of non-disease
= prevalence * (1 – prevalence) = 0.70 * (1 – 0.70)
= 2.3
Odds of the disease if test negative = Odds of non-disease * LH-
= 2.3 * 5.1
= 11.7
Neg
Statistical analyses
25
10
5
60
Sensitivity Specificity
S=25/30 (83%)
Sp=60/70 (86%)
36
PRECONGRESS COURSE 14 I VIENNA, AUSTRIA – 23 JUNE 2019 39