LQPB2504 - CMLE - The Critical Role of the Phlebotomist in the Diagnosis of Blood Stream Infections-The Critical Role of the Phlebotomist in the Diagnosis of Blood Stream Infections

The Critical Role of the Phlebotomist in the Diagnosis of Blood Stream Infections

Pdf Summary

This document from Mayo Clinic Hospital’s Department of Pathology and Laboratory Medicine (2025) focuses on the critical role of phlebotomy in diagnosing bloodstream infections (BSIs) through blood cultures. BSIs, often resulting from bacteria or fungi entering the bloodstream, can cause sepsis—a life-threatening condition marked by fever, tachycardia, and tachypnea. Blood cultures are essential diagnostic tools but are vulnerable to contamination due to the presence of skin flora like Staphylococcus epidermidis.<br /><br />The case of a kidney transplant patient developing a fever illustrates the challenges. Although blood cultures identified S. epidermidis (with antibiotic resistance), subsequent testing revealed the result was likely contamination, not true infection. Contamination arises primarily from inadequate skin sterilization before venipuncture and can lead to unnecessary antibiotic use, imaging, longer hospital stays, and patient harm.<br /><br />Best practices to reduce contamination include collecting at least two sets of blood cultures from different sites, prioritizing aerobic bottles, properly disinfecting the collection site with recommended antiseptics (e.g., chlorhexidine or iodine with alcohol), avoiding re-palpation after disinfection, changing needles before inoculating bottles, and minimizing talking during collection. Proper volume collection (8-10 mL per bottle for adults, 1-3 mL for pediatrics) also improves test sensitivity.<br /><br />The blood culture testing process involves: <br />- Preanalytical phase—patient evaluation and specimen collection with strict aseptic technique; <br />- Analytical phase—incubation and microorganism detection, identification, and susceptibility testing; <br />- Postanalytical phase—clinical interpretation to guide appropriate antimicrobial therapy.<br /><br />The document stresses that while ordering physicians hold primary responsibility for blood culture use, phlebotomists play a vital role in preventing contamination to ensure accurate diagnosis and optimal patient care. Institutions aim to keep contamination rates below 3%, ideally under 1%, with peripheral blood draws by trained phlebotomists being less prone to contamination than other methods.<br /><br />In summary, meticulous aseptic technique during venipuncture by phlebotomists is essential to avoid false-positive blood cultures that compromise patient outcomes and lead to unnecessary interventions. Proper skin antisepsis and adherence to collection protocols are key to diagnostic accuracy for bloodstream infections.

Keywords

Phlebotomy

Bloodstream infections

Blood cultures

Sepsis diagnosis

Contamination prevention

Skin antisepsis

Staphylococcus epidermidis

Blood culture protocols

Aseptic technique

Antibiotic stewardship