[Contamination of blood cultures drawn from central vein catheter and peripheral venipuncture. Prospective study of 75 pairs].
OBJECTIVE
To determine the frequency of contamination, the sensitivity, specificity, and predictive values of cultures done with blood drawn through a central venous catheter or peripheral venipuncture.


METHODS
Prospective cohort study of critical ill medical surgical intensive care patients in whom samples for paired culture were drawn through a central venous catheter or peripheral venipuncture during a period of 8 months (from August 1st 2001 to Mars 31st 2002).


RESULTS
During the study period, 75-paired cultures were studied. Fifteen peripheral blood cultures (20%) and 27 central blood cultures (36%) were positive and 6 peripheral blood cultures (8%) and 15 central blood cultures (20%) were contaminated (P=0.034). The organism most commonly responsible for contamination was Coagulase Negative Staphylococcus (16% of central blood cultures and 6.7% of peripheral blood cultures). The frequency of contamination was of 42.9% for blood cultures drawn through a femoral central venous catheter, of 10% for jugular, and of 19% for subclavian central venous catheter (P=0.22). For catheter draws compared with peripheral venipuncture, sensitivity was 100 and 75%, specificity was 76.2 and 90.5%, positive predictive value was 44.4 and 60% and negative predictive value was 100 and 95%.


CONCLUSIONS
Cultures of blood drawn through a catheter are more sensible and less specific than those obtained from a peripheral venipuncture and the organism most commonly responsible for contamination of blood cultures is Coagulase Negative Staphylococcus.
Kallel
H
H
Service de réanimation médicale, CHU Habib Bourguiba, route El-Ain, km 1, 3029 Sfax, Tunisie. Kallelhat@yahoo.fr
Dammak
H
H
Mahjoubi
F
F
Bahloul
M
M
Turki
E
E
Chelly
H
H
Rekik
N
N
Hammami
A
A
Bouaziz
M
M
D001419:Bacteria / Q000145:classification / Q000302:isolation & purification*; D001800:Blood Specimen Collection / Q000592:standards*; D002405:Catheterization, Central Venous / Q000592:standards; D002406:Catheterization, Peripheral / Q000592:standards; D003422:Critical Care / Q000592:standards; D004866:Equipment Contamination / Q000706:statistics & numerical data*; D006801:Humans; D011446:Prospective Studies; D012121:Respiration, Artificial; D012680:Sensitivity and Specificity; D014680:Veins / Q000503:physiopathology*