Table 2.
Characteristic | n | Mean±SD | Median (IQR) | Effusion culture | p Value | |
Positive, mean±SD or median (IQR) | Negative, mean±SD or median (IQR) | |||||
Blood test | ||||||
WBC (/μl) | 349 | 7549±3150 | 6960 (5700–8530) | 7755±3536 | 7189±2296 | 0.07 |
Platelet (K/μl) | 345 | 282±114 | 272 (208–347) | 262±115 | 315±106 | <0.001 |
Protein (g/dl) | 171 | 6.8±1 | 6.8 (6.1–7.5) | 6.6±1 | 7.1±1 | 0.003 |
LDH (U/litre) | 149 | 565±271 | 489 (413–644) | 509 (416–660) | 453 (379–578) | 0.03* |
Pleural effusion test | ||||||
WBC (/μl) | 369 | 2275±2000 | 1800 (900–3100) | 1600 (800–3060) | 1900 (1000–3100) | 0.17* |
Lymphocyte % | 367 | 76±25 | 84 (64–95) | 78 (55–91) | 92 (82–97) | <0.001* |
Neutrophil % | 367 | 15±21 | 5 (1–19) | 9 (2–28) | 2 (1–8) | <0.001* |
Protein (g/dl) | 362 | 4.8±1 | 5 (4.2–5.4) | 4.6±1.1 | 5±0.8 | <0.001 |
LDH (U/litre) | 362 | 988±1259 | 680 (455–1055) | 849 (500–1313) | 550 (389–763) | <0.001* |
Glucose (mg/dl) | 325 | 105±53 | 97 (77–124) | 101±56 | 112±49 | 0.07 |
Effusion-serum ratio | ||||||
Protein (effusion/serum) | 170 | 0.7±0.1 | 0.7 (0.6–0.8) | 0.7±0.1 | 0.7±0.1 | 0.84 |
LDH (effusion/serum) | 144 | 1.9±1.6 | 1.3 (0.9–2.3) | 2.1±1.8 | 1.4±1.1 | 0.01 |
p Values were calculated using Student t test unless otherwise specified.
Mann–Whitney U test.
LDH, lactate dehydrogenase; WBC, white blood cell.