Figure 1.
Figure 2.
Figure S1.
Volumes submitted for culture according to source of the material
| Blood volume measurement [ml] | Material source | p | ||
|---|---|---|---|---|
| Cord blood | Umbilical catheter | Peripheral vessel | ||
| Mean ± SD | 1.72 ± 0.78a | 1.20 ± 0.28a, b | 1.45 ± 0.40b | 0.006 |
| Range | 0.42 – 4.05 | 0.71 – 1.85 | 0.71 – 2.90 | |
Proportion of positivity with adequate and inadequate blood culture volume
| Positive blood cultures | Adequate volume cultures ≥ 1 ml | Inadequate volume cultures < 1 ml | p |
|---|---|---|---|
| True-positive | 13/179 = 7.26% | 2/26 = 7.69% | > 0.999 |
| False-positive | 8/179 = 4.47% | 1/26 = 3.85% | > 0.999 |
Volumes submitted for culture according to birthweight category
| Blood volume measurement [ml] | Birthweight | All birthweight category samples | p | ||
|---|---|---|---|---|---|
| ≤ 1500 g | 1501–2500 g | > 2500 g | |||
| Mean ± SD | 1.38 ± 0.42a | 1.49 ± 0.56 | 1.68 ± 0.70a | 1.52 ± 0.58 | 0.004 |
| Range | 0.42 – 2.68 | 0.68 – 3.53 | 0.69 – 4.05 | 0.42 – 4.05 | |
Blood culture submissions characteristics
| n (%) | |
|---|---|
| Samples weighed | 205 (100.0) |
| Samples with volume estimation | 196 (95.6) |
| Birthweight | 205 |
| ≤ 1500 g | 53 (25.9) |
| 1501–2500 g | 90 (43.9) |
| > 2500 g | 62 (30.2) |
| Material source | 205 |
| Cord blood | 72 (35.1) |
| Umbilical catheter | 20 (9.8) |
| Peripheral vessel | 112 (54.6) |
| Not specified | 1 (0.5) |
| Positive blood cultures | 24 |
| True-positive blood cultures | 15 (62.5) |
| False-positive blood cultures | 9 (37.5) |
Comparison of blood volume measurement versus estimation
| Blood volume measurement [ml] | ||||
|---|---|---|---|---|
| < 1 ml | ≥ 1 ml | Total | ||
| Blood volume estimation [ml] | < 1 ml | 4 (2.0) | 1 (0.5) | 5 (2.6) |
| ≥ 1 ml | 22 (11.2) | 169 (86.2) | 191 (97.4) | |
| Total | 26 (13.3) | 170 (86.7) | 196 (100.0) | |
Medical personnel opinion on difficulty of blood culture collection and necessity of blood sample measurement_
| Total group | Doctors | Nurses | p | |
|---|---|---|---|---|
| n | 36 | 14 | 22 | |
| Blood culture collection is: | ||||
| Easy | 11 (30.6) | 6 (42.9) | 5 (22.7) | 0.469 |
| Moderately difficult | 21 (58.3) | 7 (50.0) | 14 (63.6) | |
| Difficult | 4 (11.1) | 1 (7.1) | 3 (13.6) | |
| Don’t know | - | - | - | |
| Measurement of blood volume collected for culture is: | ||||
| Unnecessary | 2 (5.6) | - | 2 (9.1) | 0.244 |
| Necessary, but a substantial impediment | 3 (8.3) | 1 (7.1) | 2 (9.1) | |
| Necessary and not a substantial impediment | 27 (75.0) | 13 (92.9) | 14 (63.6) | |
| Don’t know | 4 (11.1) | - | 4 (18.2) | |