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. 2011 Jan;6(1):22-7.
doi: 10.1002/jhm.711. Epub 2010 Jul 13.

Age-specific Reference Values for Cerebrospinal Fluid Protein Concentration in Neonates and Young Infants

Free PMC article

Age-specific Reference Values for Cerebrospinal Fluid Protein Concentration in Neonates and Young Infants

Samir S Shah et al. J Hosp Med. .
Free PMC article


Background: Cerebrospinal fluid (CSF) protein values decline over the first few months of life as the infant's blood-CSF barrier matures. However, published studies differ in the reported rate, timing, and magnitude of this decline.

Objective: To quantify the age-related changes in CSF protein concentration and to determine accurate, age-specific reference values for neonates and young infants.

Design, setting and patients: This cross-sectional study included infants age 56 days or younger who had a lumbar puncture performed in the emergency department of an urban tertiary care children's hospital between January 1, 2005 and June 30, 2007. Infants with conditions associated with elevated CSF protein concentrations, including traumatic lumbar puncture and bacterial or viral meningitis, were excluded.

Results: Of 1064 infants undergoing lumbar puncture, 375 (35%) met inclusion criteria. The median CSF protein value was 58 mg/dL (interquartile range: 48-72 mg/dL). In linear regression, the CSF protein concentration decreased 6.8% (95% confidence interval [CI], 5.4%-8.1%; P < 0.001) with each 1 week increase in age. The 95th percentile values were 115 mg/dL for infants ≤28 days and 89 mg/dL for infants 29-56 days. The 95th percentile values by age category were as follows: ages 0-14 days, 132 mg/dL; ages 15-28 days, 100 mg/dL; ages 29-42 days, 89 mg/dL; and ages 43-56 days, 83 mg/dL.

Conclusions: We quantify the age-related decline in CSF protein concentration among infants 56 days of age and younger and provide age-specific reference values. The values reported here represent the largest series to-date for this age group.


Figure 1
Figure 1
Relationship of cerebrospinal fluid protein concentration and age. Each circle represents data from one infant. A linear regression line shows the rate of decline in protein concentration with age.
Figure 2
Figure 2
Boxplot showing variation in cerebrospinal fluid protein concentrations by age category. The line in the middle of the box denotes the median value. The ends of the boxes represent the interquartile range (i.e., 25th and 75th percentile) values. The whiskers extend 1.5 times the interquartile range values and the circles denote extreme outlying values.

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