Intraosseous (IO) blood is frequently used to establish a blood chemistry profile in critically ill patients. Questions remain regarding the reliability of IO blood for laboratory analysis and established criteria regarding the amount of marrow/blood to waste before taking an IO sample are not available.
To evaluate IO-derived blood for routine laboratory blood tests needed in the care of critically ill patients and to determine the amount of marrow/blood to waste before drawing blood from the IO space for laboratory analysis.
Blood samples were drawn from peripheral veins of 10 volunteers. Within 5 minutes, 2 IO blood samples were obtained; one following 2 mL of waste and another following 6 mL of waste. Samples were analyzed for complete blood count and chemistry profile. Values were analyzed using Pearson correlation coefficients. Levels of significance were determined using the t distribution. Mean values for the draws were calculated and compared, with the intravenous blood sample serving as a control for the IO samples.
There was a significant correlation between intravenous and IO samples for red blood cell counts and hemoglobin and hematocrit levels but not for white blood cell counts and platelet counts. There was a significant correlation between intravenous and IO samples for glucose, blood urea nitrogen, creatinine, chloride, total protein, and albumin concentrations but not for sodium, potassium, CO(2), and calcium levels.
When venous blood cannot be accessed, IO blood aspirate may serve as a reliable alternate, especially for hemoglobin and hematocrit levels and most analytes in a basic blood chemistry profile. Exceptions are CO(2) levels and platelet counts, which may be lower, and white blood cell counts, which may appear elevated.