CEREBROSPINAL-FLUID BETA(2)-MICROGLOBULIN IN NEONATES WITH CENTRAL-NERVOUS-SYSTEM INFECTIONS

Beta(2)-microglobulin (beta(2)m) determination in CSF of 72 neonates w ho underwent a spinal tap as part of a sepsis or meningo-encephalitis workup was performed to evaluate the usefulness of this test in the di ag nosis of CNS infections. beta(2)m was measured by enzyme immunoassa y. Sixty neonates had sterile culture and normal neurological status a t discharge. Twelve infants had CNS infections: 8 bacterial meningitis , 3 TORCH infections (T = toxoplas mosis, O = others, R = rubella, C = cytomegalovirus and H=herpes simplex) and I viral meningitis. Neonate s with CNS infection exhibited significantly higher CSF beta(2)m level s compared to neonates with sterile culture (6.24 +/- 2.66 vs 1.74 +/- 0.5 mg/l; P < 0.0001). CSF beta(2)m levels did not correlate with the white cell count, total protein concentration or glucose level in CSF When serum and CSF levels were measured simultaneously, the CSF beta( 2)m level was significantly higher than the corresponding serum level in patients with CNS infection (6.98 +/- 2.5 vs 3.2 +/- 0.25 mg/l; P < 0.01). Sensitivity, specificity, and predictive values were estimated for different cut-off points. The best operational diagnostic cut-off value was 2.25 mg/l. Receiver operating characteristic curve analysis showed an appropriate trade-off between specificity and sensitivity a nd indicated that CSF beta(2)m was accurate in distinguishing between neonates with and without CNS infection. Conclusion CSF beta(2)m may b e a useful ancillary tool in neonates when CNS infection is suspected.