Changes in A and D, CSF WBC count (A and D), CSF protein level C and F, and CSF glucose level with increasing postnatal age in preterm and term infants. The graphs exclude infants with unknown CSF WBC concentration (n = 1) or an extremely outlying value (n = 1; CSF WBC of 850), unknown CSF protein concentration (n = 4), and unknown CSF glucose concentration (n = 2). The solid lines represent the best linear fit for each laboratory test result; the dashed lines represent upper limits (for CSF WBC and protein) and lower limits (for CSF glucose) based on the addition or subtraction of 1.5 × IQR to the upper or lower limit of the IQR, respectively; and the dotted lines represent upper limits (for CSF WBC and protein) and lower limits (for CSF glucose) based on the 95th and 5th percentile values, respectively. The vertical line represents a postnatal age of 7 days.