Normal reference values for testing of cerebrospinal fluid in term and preterm infants

Abstract

Srinivasan et al have provided a valuable service to clinicians and infants worldwide by performing and analyzing in an exacting way the cerebrospinal fluid (CSF) findings of preterm and term infants who did not have central nervous system infections. Their findings provide most reliable, clinically relevant cutpoints for normal findings that we ever have had or likely will have in the future. Contrary to tenets from previously published data, CSF white blood cell counts in preterm and term infants are similar and are low (upper bound cutpoints of 14 cells/mm3), even in the first week of life. This study is superior to others in the past, most notably because of careful exclusion criteria and prospective approach that aided correct patient categorization and minimized missing data. An important caveat is that infants with CSF red blood cell counts of >500 cells/mm3, presumably from hemorrhage, birth trauma, or traumatic lumbar puncture, were excluded. Inclusion of such infants in prior studies speculatively could be a major reason why we held as “normal” higher limits of white blood cell counts and protein concentrations. It is noteworthy that 30% of infants evaluated for inclusion in the study were excluded because of high red blood cell counts. Findings are not generalizable to this group.The additional finding that short-term antibiotic therapy prior to lumbar puncture did not affect cutpoints in a clinically meaningful way will be most useful in settings in the neonatal intensive care unit, when cardiorespiratory instability precludes CSF examination prior to therapy and when CSF is only successfully obtained 1-2 days after treatment of neonates admitted from emergency departments.Article page 729▶ Srinivasan et al have provided a valuable service to clinicians and infants worldwide by performing and analyzing in an exacting way the cerebrospinal fluid (CSF) findings of preterm and term infants who did not have central nervous system infections. Their findings provide most reliable, clinically relevant cutpoints for normal findings that we ever have had or likely will have in the future. Contrary to tenets from previously published data, CSF white blood cell counts in preterm and term infants are similar and are low (upper bound cutpoints of 14 cells/mm3), even in the first week of life. This study is superior to others in the past, most notably because of careful exclusion criteria and prospective approach that aided correct patient categorization and minimized missing data. An important caveat is that infants with CSF red blood cell counts of >500 cells/mm3, presumably from hemorrhage, birth trauma, or traumatic lumbar puncture, were excluded. Inclusion of such infants in prior studies speculatively could be a major reason why we held as “normal” higher limits of white blood cell counts and protein concentrations. It is noteworthy that 30% of infants evaluated for inclusion in the study were excluded because of high red blood cell counts. Findings are not generalizable to this group. The additional finding that short-term antibiotic therapy prior to lumbar puncture did not affect cutpoints in a clinically meaningful way will be most useful in settings in the neonatal intensive care unit, when cardiorespiratory instability precludes CSF examination prior to therapy and when CSF is only successfully obtained 1-2 days after treatment of neonates admitted from emergency departments. Article page 729▶ Cerebrospinal Fluid Reference Ranges in Term and Preterm Infants in the Neonatal Intensive Care UnitThe Journal of PediatricsVol. 161Issue 4PreviewTo determine reference ranges of cerebrospinal fluid (CSF) laboratory findings in term and preterm infants in the neonatal intensive care unit. Full-Text PDF