The Effect of Contrast Media on Several Common Laboratory Assays

Abstract: Contrast media are commonly used as an enhancement in several diagnostic imaging methods, which in today’s healthcare often are combined with blood works in diagnostics and surgical preparations, as well as to follow up on the patient’s recovery. To save time and money for both the hospital and the patients themselves, the ability to carry out both the radiological examination and the blood works within the same hospital visit would be preferred. However, there have been indications of a potential interference from the contrast media used, and therefore a waiting period is in place. The aim of this study was therefore to see if that waiting period was warranted by testing if contrast media does cause a significant interference in the most common analyses. This was investigated by infusing pooled samples with either iohexol or gadoteric acid, the active components of the most common contrast agents, at either a full dosage or a half dosage. These samples were then run by standard protocol and the results compared to control samples. The results showed that while some analyses proved affected, others proved unaffected or only insignificantly so. Some of the affected analyses were sodium, activated partial thrombin time and hemoglobin. While some analyses such as prostate specific antigen and prothrombin time were unaffected. Analysis of more samples is necessary to confirm the results, but the overall consensus is that while most analyses are unaffected the effects are too large and uncertain to comfortably disregard the waiting time.