Posttest probability* (5% pretest probability†)		Posttest probability* (25% pretest probability†)
Finding	LR+‡	LR−‡	Finding present	Finding absent	Finding present	Finding absent
Pelvic inflammatory disease
Purulent endocervical discharge	3.3	0.8	15	4	52	21
Abdominal rebound tenderness	2.5	0.8	12	4	45	21
Fever	1.3	0.8	6	4	30	21
Leukocyte count > 10,500 per mm3 (10.50 × 109 per L)	1.3	0.9	6	5	30	23
Erythrocyte sedimentation rate > 15 mm per hour	1.2	0.6	6	3	29	17
Cervical motion tenderness	1.1	0.9	5	5	27	23
Pelvic organ tenderness	1.0	1.0	5	5	25	25
Ectopic pregnancy
Finding of any noncystic, extraovarian adnexal mass on ultrasonography	27.0	0.01	59	0	90	0
β-hCG < 1,000 mIU per mL (1,000 IU per L)§	3.6	0.7	16	4	55	19
Indeterminate ultrasonography and β-hCG < 1,000 mIU per mL§	2.6	0.4	12	2	46	12
Appendicitis
Right lower quadrant abdominal pain	8.4	0.2	31	1	74	6
Pain migration from periumbilical area to the right lower quadrant of the abdomen	3.6	0.4	16	2	54	13
Fever	3.2	0.4	14	2	51	12
Psoas sign	3.2	0.9	14	4	52	23
Rebound tenderness	2.0	0.5	10	3	40	15
Rigidity	1.6	0.9	9	5	38	23