Table 2. Diagnostic performance of different numbers of specimens for evaluating axillary lymph node metastasis.

Measure	Specimen 1 (%)	Specimen 1–2 (%)	Specimen 1–3 (%)	Specimen 1–4 (%)
Sensitivity	74.2 (109/147) (66.3–81.0)	87.8 (129/147) (81.3–92.6)	91.2 (134/147) (85.4-95.2)	94.6 (139/147) (89.6–97.6)
Specificity	100% (20/20) (83.2–100)	100% (20/20) (83.2–100)	100% (20/20) (83.2–100)	100% (20/20) (83.2–100)
Negative predictive value	34.5 (20/58) (22.5–48.1)	52.6 (20/38) (35.8–69.0)	60.6 (20/33) (42.1–77.1)	71.4 (20/28) (51.3–86.8)
Positive predictive value	100% (109/109) (96.7–100)	100% (129/129) (96.7–100)	100% (134/134) (96.7–100)	100% (139/139) (96.7–100)
Accuracy	77.3 (129/167) (70.9–83.7)	89.2 (149/167) (84.5–93.4)	92.2 (154/167) (88.1–96.3)	95.2 (159/167) (92.0–98.4)

Data in parentheses are numbers used to calculate percentages, and data in brackets are 95% confidence intervals.