Rate of Blood Culture Contamination as an Indicator of Quality of patient care - a retrospective study

Background: Blood cultures are one of most important diagnostic tool and indicator of quality of care. Contamination of blood samples is not only challenging to make accurate diagnosis but also results in undue use of antibiotics and wastage of hospital resources. This also poses a potential risk to patient's life. American Society of Microbiology recommends annual blood culture contamination rate to be less than 3%. Aim: To estimate the rate of blood culture contamination and the factors contributing to it. Method: Blood cultures records from 1st Jan to 31st Dec, 2019 in the microbiology laboratory of Fatima Memorial Hospital, Lahore were evaluated retrospectively. Results: Annual rate of blood culture contamination was 5%. Maximum number of contaminants was found in the months of June, July and August with highest in July where contamination rate reached to 13.6%. The highest number (56.9%) of study population was children under 5 years of age. Thepredominant isolate was Coagulase negative Staphylococcus (90.2%). The highest blood contamination (32.9%) was observed in Pediatric emergency and ICU succeeded by medical outdoors (16.9%). Conclusion: Annual rate of blood culture contamination at FMH was more than the acceptable international range. The highest rate was observed during summer season. Pediatric units reported the maximum number of contaminants. Comprehensive plan of training the relevant personnel is required with strict monitoring to minimize contamination.