Standardizing Patient’s Posture During Blood Collection by Venipuncture

The clinical laboratory standard institute (CLSI) H3A6 document (presently renamed to CLSI GP41-A6) contains specific information regarding patient’s posture during blood collection by venipuncture, stating that “specimens should be drawn with the patient seated comfortably in an appropriate chair or lying down” (1). The world health organization (WHO) guidelines on blood drawing contain a different indication, as follows: “make the patient comfortable in a supine position (if possible)” (2). Consequently, healthcare professionals often assume that these two postural positions-either supine or sitting-could be interchangeable, and the shift from one posture to the other may not generate significant bias on laboratory testing. It is noteworthy that inpatients blood samples can be drawn at different moments and postures, e g, in sitting position during the day, and in supine position during the night. On the other hand, outpatients (e g, patients attending for blood collection sites) usually do not maintain a definite and/or stable position before venipuncture. Consequently, samples are frequently drawn from subjects who indifferently walked or remained standing for long time, or remained seated for short time-e.g., seated less than three minutes at phlebotomy room-before blood collection.