Table 3.
Blood inoculant volume from weighing bottles
| Total | Birth weight >1500 grams |
VLBW & culture obtained ≤7 days | VLBW & culture obtained >7 days | p-value | |
|---|---|---|---|---|---|
| Blood culture evaluationa, n | 544 | 380 | 60 | 104 | |
| Total volume (mL) per evaluation, median (IQR) | 2.0 (1.8–2.3) | 2.1 (1.9–2.3) | 2.0 (1.7–2.1) | 1.8 (1.2–2.1) | <0.001 |
| ≥1 mL per evaluation, n (%) | 508 (93.4) | 362 (95.3) | 57 (95.0) | 89 (85.6) | 0.002 |
| <1 to 0.5 mL per evaluation, n (%) | 33 (6.1) | 17 (4.5) | 2 (3.3) | 14 (13.5) | 0.002 |
| <0.5 mL per evaluation, n (%) | 3 (0.5) | 1 (0.3) | 1 (1.7) | 1 (1.0) | 0.32 |
| At least one bottle with ≥1 mL, n (%) | 418 (76.8) | 307 (80.8) | 43 (71.7) | 68 (65.4) | 0.003 |
| Aerobic culture bottlesa, n | 539 | 378 | 59 | 102 | |
| Volume (mL) in aerobic bottle, median (IQR) | 1.0 (0.9–1.2) | 1.1 (0.9–1.2) | 1.0 (0.8–1.1) | 1.0 (0.8–1.2) | 0.03 |
| ≥1 mL in aerobic bottle, n (%) | 304 (56.4) | 224 (59.3) | 28 (47.5) | 52 (51.0) | 0.11 |
| <1 to 0.5 mL in aerobic bottleb, n (%) | 225 (41.7) | 147 (38.9) | 30 (50.9) | 48 (47.1) | 0.11 |
| <0.5 mL in aerobic bottle, n (%) | 10 (1.9) | 7 (1.9) | 1 (1.7) | 2 (2.0) | 0.99 |
| Anaerobic culture bottlesa, n | 472 | 348 | 53 | 71 | |
| Volume (mL) in anaerobic bottle, median (IQR) | 1.0 (0.9–1.2) | 1.1 (1.0–1.2) | 1.0 (0.9–1.2) | 1.0 (0.9–1.1) | 0.004 |
| ≥1 mL in anaerobic bottle, n (%) | 280 (59.3) | 220 (63.2) | 28 (52.8) | 32 (45.1) | 0.01 |
| <1 to 0.5 mL in anaerobic bottleb, n (%) | 176 (37.3) | 117 (33.6) | 25 (47.2) | 34 (47.9) | 0.02 |
| <0.5 mL in anaerobic bottle, n (%) | 16 (3.4) | 11 (3.2) | 0 (0) | 5 (7.0) | 0.09 |
Abbreviations: VLBW – very low birth weight, IQR – interquartile range
a
Blood culture evaluation includes all culture bottles sent per evaluation and may include one bottle or a pair of bottles. Inoculant volume per bottle is shown separately.
b
When inoculant volume was <1 to 0.5 mL, 156/225 (69%) aerobic bottles and 140/176 (80%) anaerobic bottles had volume of 0.8 to <1 mL.