Table 4.

Positive and negative predictors for malignancy

Predictor		Malignancy	No malignancy	Predictive value
Examination	Abnormal	9	49	PPV 15.5% NPV 99.4%
Normal	1	169
Mammography	Abnormal (M3, M4, M5)	8	7	PPV 53.3% NPV 98.2%
Normal (M1, M2)	2	111
Ultrasonography	Abnormal (U3, U4, U5)	8	15	PPV 65.2% NPV 99.3%
Normal (U1, U2)	1	147
Discharge colour	Bloody	4	78	PPV 4.9% NPV 93.1%
Non-bloody	6	81
Ductal source	Uniductal	6	141	PPV 4.1% NPV 100%
Multiductal	0	33
Red blood cells	Present	2	31	PPV 6.1% NPV 96.9%
Absent	4	127
Epithelial cells	Present	3	25	PPV 10.7% NPV 97.1%
Absent	3	100

NPV = negative predictive value; PPV = positive predictive value