Purpose <p>Hypersensitivity reactions are a side effect of bleomycin. Test doses have been utilized to attempt to predict patients who would develop these reactions. Despite this, there is scant data available on whether these test doses actually predict the development of reactions. Commonly cited literature relies on a lack of reporting of hypersensitivity reactions, rather than comparative data, to claim test doses may not be beneficial. The purpose of this analysis was to compare patients who received test doses against those who did not in the development of bleomycin hypersensitivity reactions.</p> Methods <p>A total of 77 patients who had received bleomycin as part of their chemotherapy regimen were included in this retrospective analysis. Patients were stratified based on the receipt of a bleomycin test dose (either 1 or 2 units given prior to the full dose). The presence of hypersensitivities was assessed by documentation of emergency medications in the medical record shortly after bleomycin administration or through documentation by a provider note.</p> Results <p>There were no reactions reported with any of the 84 test doses administered. With the full dose of bleomycin administered, hypersensitivity reactions occurred in three patients in the test dose arm (5.5%) compared to no patients in the group that did not receive a test dose. Despite this difference, there was no statistical difference between the two arms (<i>p</i> = 0.264).</p> Conclusion <p>In this study, we observed no relation between a negative bleomycin test dose and the development of acute hypersensitivity reaction. Interestingly, there was a higher numerical incidence of hypersensitivity reactions in patients who received a test dose than those who did not receive a test dose, though this was not statistically significant. Larger studies would need to be conducted to verify these findings.</p>