Effect of delay in analysis on neonatal cerebrospinal fluid parameters.
OBJECTIVE
The effect of delayed analysis on cerebrospinal fluid (CSF) white blood cell (WBC) count and glucose has never been studied in neonates.


METHODS
Prospective cohort study.


METHODS
Level III newborn unit.


METHODS
Neonates undergoing lumbar puncture were enrolled after consent. CSF was analysed at baseline (30 minutes) for protein, WBC and glucose; and from the same sample for WBC and glucose after a lag of 2 h and 4 h after lumbar puncture. Those with traumatic/inadequate CSF were excluded. Subjects were classified in three groups (n = 20 each) based on baseline WBC count: no WBC, 1-30 WBC and >30 WBC/microl. Analysis was by repeated-measures ANOVA.


RESULTS
There was a significant decline in mean (SD) CSF glucose from baseline to 2 h and 4 h (41.0 (19) to 38.3 (19) and 36.2 (20) mg/dl, respectively) and WBC count (36 (45) to 28.6 (38) and 23.8 (34) cells/microl, respectively; both p<0.001). CSF glucose and WBC declined in all three groups (p<0.001). High baseline CSF WBC (p<0.001) and protein (p<0.001) was associated with a more rapid decline in the levels of CSF WBC, but not glucose. True CSF parameters could be predicted from 4-h parameters: "baseline glucose 5.4 + 0.98 (4-h glucose)" (adjusted R(2) 97.2%, p<0.001) and "baseline WBC 1.3 (4-h WBC) +0.05 (protein)" (adjusted R(2) 98.8%, p<0.001). In group 3, a diagnosis of meningitis (based on pleocytosis) would be missed in 52.6% and 78.9% subjects at 2 h and 4 h, respectively.


CONCLUSIONS
CSF WBC count and glucose decrease significantly with time. Reliance on WBC counts of delayed samples can result in underdiagnosis.
Rajesh
N T
NT
Department of Pediatrics, PGIMER, Chandigarh 160012, India.
Dutta
Sourabh
S
Prasad
Rajendra
R
Narang
Anil
A
D000704:Analysis of Variance; D002556:Cerebrospinal Fluid Proteins / Q000032:analysis; D019411:Clinical Laboratory Techniques; D015331:Cohort Studies; D057210:Delayed Diagnosis; D005188:False Negative Reactions; D005260:Female; D005865:Gestational Age; D005947:Glucose / Q000134:cerebrospinal fluid*; D006801:Humans; D007194:India; D007231:Infant, Newborn; D007234:Infant, Premature / Q000134:cerebrospinal fluid; D007235:Infant, Premature, Diseases / Q000134:cerebrospinal fluid* / Q000175:diagnosis; D007958:Leukocyte Count; D007964:Leukocytosis / Q000134:cerebrospinal fluid; D008297:Male; D016920:Meningitis, Bacterial / Q000134:cerebrospinal fluid* / Q000175:diagnosis; D009504:Neutrophils / Q000166:cytology; D012016:Reference Values; D013129:Spinal Puncture; D013997:Time Factors
D002556:Cerebrospinal Fluid Proteins; D005947:Glucose