Background Patients with suspected alcoholic hepatitis and a Discriminant Function ≥32 underwent liver biopsy to confirm the diagnosis. Of these (n = 58), 43 had histological features of alcoholic hepatitis and 15 (25%) did not. We aimed to determine the laboratory features that differentiated those patients with a histological diagnosis of alcoholic hepatitis from those without, and assess potential clinical utility. Methods Laboratory investigations at presentation for each of the histologically confirmed cases of alcoholic hepatitis (n = 43) were compared to those without (n = 15) to determine whether there were differences between the two groups. Univariate analysis was by Mann Whitney U Test and Multivariate analysis was by a stepwise approach. Results White cell count (16.2 ± 10.5 v 6.9 ± 3.5 (× 109/L); p = 0.0001) and platelet count (178 ± 81 v 98.4 ± 43 (× 109/L); p = 0.0005) were higher in the patients with histological features of alcoholic hepatitis than in those without. The area under the ROC curve for AH diagnosis was estimated to be 0.83 (0.73, 0.94) and 0.81 (0.69, 0.93) for white cell count and platelet count respectively. Conclusions Clinicians cannot accurately differentiate patients with or without alcoholic hepatitis without liver biopsy. This is critically important when deciding on specific therapies such as corticosteroids or when interpreting data from future trials in which biopsy is not mandated. In situations where liver biopsy is unsuitable or unavailable the white cell and platelet counts can be used to determine the likelihood of histological alcoholic hepatitis and guide treatment.