[Blood volume for biochemistry determinations--laboratory needs and everyday practice]

Area of Science:

• Clinical Biochemistry
• Pediatric Medicine
• Laboratory Hematology

Background:

• Diagnostic phlebotomy, particularly in neonates, infants, and critically ill patients, poses a significant risk of iatrogenic anemia due to repeated blood loss.
• While adults tolerate single blood draws, vulnerable populations are susceptible to anemia from frequent laboratory monitoring.

Purpose of the Study:

• To assess the volume of blood collected for routine biochemistry tests in relation to patient age and the number of parameters ordered.
• To identify factors influencing blood draw volumes in pediatric and adult patient populations.

Main Methods:

• Blood samples from 2980 children (1 day-18 years) and 859 adults (>1.8 years) at University Hospitals in Cracow were analyzed.
• Blood volume was calculated based on tube dimensions and microvette volumes (0.2 ml).
• Statistical analysis was performed using PRISM 5.0 with significance set at p < 0.05.

Main Results:

• Mean blood volumes were 3.02 ± 0.92 ml for children and 4.12 ± 0.68 ml for adults.
• In children, blood volume significantly correlated with patient age (p < 0.001) and the number of requested parameters (p < 0.001) up to five parameters.
• Microvette use was highest in newborns/infants and for 1-3 tests; this correlation was not observed when only regular tubes were used.

Conclusions:

• Educational programs for healthcare professionals should emphasize current laboratory automation and method miniaturization.
• Clinicians must consider the actual blood volume required by the laboratory for requested tests during diagnostic phlebotomy, especially in pediatric patients.