A study, published in Infection Control & Hospital Epidemiology, examined clinical variables that influence the volume of blood collected for blood cultures.
Researchers conducted the study at an academic medical center with a clinical laboratory that processes 20,000-plus blood cultures annually and includes a dedicated phlebotomy staff for venipuncture. They determined blood volume in 568 culture bottles from 128 unique adult patients over a six-day period. They also extracted clinical data from the time of phlebotomy from EMRs.
Researchers found that blood samples obtained from a central venous catheter yielded, on average, 2.53 mL more blood than those from peripheral venipuncture. Additionally, aerobic bottles contained 0.38 mL more blood than the anaerobic bottles. The remaining clinical variables did not reach statistical significance in relation to volume.
"These data highlight the clinically significant issue of low culture volume recovery, indicate that diagnostic and prognostic tools that rely on volume-dependent phenomena (ie, time to positivity) may require further validation under usual clinical practice circumstances, and suggest goals for future institutional performance improvement," study authors concluded.