ALBUMIN QUOTIENT, IGG CONCENTRATION, AND IGG INDEX DETERMINATIONS IN CEREBROSPINAL-FLUID OF NEONATAL FOALS

Total protein (TP), albumin, and IgG concentrations were measured in C SF from the atlanto-occipital (AO) and lumbosacral (LS) sites and in s erum of 15 clinically normal neonatal foals less than or equal to 10 d ays old (mean, 7.0 days). The albumin quotient (AQ; CSF albumin/ serum albumin x 100) and IgG index ([csF IgG/ serum IgG] x [serum albumin/C SF albumin]), indicators of blood-brain barrier permeability and intra thecal IgG production, respectively, were then calculated. Mean +/- SD values obtained from the foals of this study were: serum albumin, 2,9 00 +/- 240 mg/dl; serum IgG, 1,325 +/- 686 mg/dl; AO CSF total protein (TP), 82.8 +/- 19.2 mg/dl; LS CSF TP, 83.6 +/- 16.1 mg/dl; AQ CSF alb umin, 52.0 +/- 8.6 mg/dl; LS CSF albumin, 53.8 +/- 15.7 mg/dl; AO CSF IgG, 10.2 +/- 5.5 mg/dl; LS CSF igG, 9.9 +/- 5.7 mg/dl; AO AQ, 1.86 +/ - 0.29; LS AQ, 1.85 +/- 0.51, AO IgG index, 0.52 +/- 0.28; and LS IgG index, 0.48 +/- 0.27. Significant difference between values for the AO and LS sites was not found. A CSF albumin concentration > 85.2 mg/dl or AQ > 2.4, as determined by mean +/- 2 SD, may indicate increased bl ood-brain barrier permeability. An IgG index value > 1.0 may indicate intrathecal IgG production. Values obtained for foals of this study sh ould serve as baseline for comparison in the evaluation of blood-brain barrier permeability and intrathecal IgG production in neonatal foals with neurologic disease.