The influence of alcohol and time on the S-100B levels of patients with minor head injury.

The present study aimed at evaluating the S-100B serum level's reaction to (i) alcohol consumption and (ii) time elapsing between head injury and blood sampling. Nineteen patients with minor head trauma and with at least one of the following symptoms: amnesia, transient loss of consciousness or severe headache, were included in the study. Immediately after arrival venous blood samples were drawn for determination of alcohol concentration and S-100B level. Four hours later a new blood sample was taken for repeat analysis. Twenty-one healthy volunteers drank a moderate amount of alcohol. Blood samples were taken just before alcohol intake and 4 h later. Patients - After 4 h the mean S-100B level had fallen from 0.26 to 0.21 ng/ml (P < 0.01), i.e. a mean decrease of 0.05 ng/ml, 95% confidence limits: 0.02-0.09 ng/ml. The alcohol concentrations also decreased significantly from 2.00 +/- 0.27 per thousand to 1.31 +/- 0.20 per thousand, P < 0.001, mean difference = 0.69 per thousand, 95% confidence limits: 0.27-1.11 per thousand. No difference was found between the S-100B levels of patients whose serum did contain alcohol and the levels of those whose serum did not. Volunteers - The serum alcohol level reached a mean value of 0.81 per thousand +/- 0.09 per thousand. The mean S-100B level rose from 0.077 +/- 0.02 ng/ml before alcohol intake to 0.103 +/- 0.06 ng/ml, 4 h later (P < 0.01). These data indicate that the time that elapses between trauma and blood test has an effect on the S-100B level. The same goes for the drinking of even a very moderate amount of alcohol. The relative importance of these two sources of error remains to be determined.