Correction of ventricular cerebrospinal fluid (CSF) samples for blood content does not increase sensitivity and specificity for the detection of CSF infection.
BACKGROUND
Blood contamination is commonly observed in ventricular cerebrospinal fluid (CSF) samples from patients with extraventricular drainage systems. Because the introduction of blood may interfere with the white blood cell count as a useful marker for the diagnosis of an infection, correction for blood content would be desirable.


METHODS
In a retrospective study, we analysed the use of correction formulas in 724 blood-contaminated ventricular CSF samples.


RESULTS
Using a standard correction method the white blood cell count was not normalised in most CSF samples, with pleocytosis indicating an inflammatory stimulus set by the blood itself or by the foreign body. When correcting white blood cell counts in the CSF of culture-positive patients, some samples were normalised or overcorrected. In addition, correction of the CSF white blood cell count did not increase sensitivity and specificity for the detection of culture-positive CSF samples.


CONCLUSIONS
Correction is not necessary when using the white blood cell count as a parameter to predict CSF infection in ventricular CSF samples.
Boeer
Klas
K
Institut für Klinische Chemie und Laboratoriumsdiagnostik, Friedrich Schiller University, Jena, Germany. klas.boeer@med.uni-jena.de
Siegmund
Robert
R
Pfister
Wolfgang
W
Isenmann
Stefan
S
Deufel
Thomas
T
D020806:Central Nervous System Bacterial Infections / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D002555:Cerebrospinal Fluid / Q000166:cytology*; D004322:Drainage; D004906:Erythrocyte Count; D006801:Humans; D007958:Leukocyte Count; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity