Reye's Syndrome can be considered excluded if one or more of the following findings are present:
(1) normal AST and ALT
(2) no necrosis and inflammation on liver biopsy
(3) no steatosis on liver biopsy
(4) no significant mitochondrial alterations seen on electron microscopy
(5) a cause for the acute illness can be identified
Reye's syndrome is considered unlikely if:
(1) the case has not already been classified as certain, probable or excluded, OR if
(2) two or more of the following are present
(2a) total bilirubin level >= 51 µmol/L
(2b) normal serum ammonia level, if stage 2 or greater
(2c) a threefold or greater increase in creatinine level
(2d) focal neurologic signs are present
(2e) myocardial damage is present
(2f) no prodromal illness present if >= 12 months of age
(2g) shock present on admission
(2h) CSF protein level >= 0.5 g/L
