Table 1.
Reference blood sampling volumes for research purposes in children by body weight: single time point and any 4-week period
| Body weight (kg) | TBV (mL)* | Single time point, ≤ 1% TBV (mL) | Any 4 weeks, ≤ 3% TBV (mL)† |
|---|---|---|---|
| Neonates (first 28 days): TBV 100 mL/kg | |||
| 2.5 | 250 | 2.5 | 7.5 |
| 3 | 300 | 3.0 | 9.0 |
| 3.5 | 350 | 3.5 | 10 |
| Infants, children and adolescents: TBV 80 mL/kg | |||
| 4 | 320 | 3.2 | 9.6 |
| 6 | 480 | 4.8 | 14 |
| 7.5 | 600 | 6.0 | 18 |
| 10 | 800 | 8.0 | 24 |
| 12 | 960 | 9.6 | 28 |
| 14 | 1120 | 11 | 33 |
| 18 | 1440 | 14 | 43 |
| 22 | 1760 | 17 | 52 |
| 28 | 2240 | 22 | 67 |
| 34 | 2720 | 27 | 81 |
| 42 | 3360 | 33 | 100 |
| 52 | 4160 | 41 | 124 |
| 62 | 4960 | 49 | 148 |
*TBV, total blood volume, calculated according to the European recommendations as 100 mL/kg in neonates and 80 mL/kg in older infants, children and adolescents, the lower end of the 80–90 mL/kg range [4]. In neonates, 1% of TBV therefore equals 1 mL/kg. In neonates who already need much clinical sampling, and in preterm infants, even these volumes may be excessive [4]
†Cumulative research-related blood loss, including waste, in any rolling 4-week period. Volumes below 10 mL are given to one decimal place; larger volumes are rounded down to whole millilitres. All values are reference values, not universal regulatory limits