Background Appropriate indications for radiologic evaluation of central venous ports are not fully understood. We aimed to quantitatively assess the utility of clinical history and imaging in the evaluation of malfunctioning central venous ports. Methods Clinical history, plain radiographs, and line injections intended to evaluate central venous port malfunction in 153 consecutive cases over a nearly 4-year period were retrospectively reviewed by 2 radiologists. Radiographs and line injections were separately categorized as normal or abnormal, and a consensus was reached on the final imaging diagnosis. The likelihood of a port-related abnormality necessitating immediate intervention was determined for all represented combinations of clinical history, radiographic findings, and line injection results. Results A radiologic diagnosis was made in 96.1% of cases; 19.7% of these diagnoses were classified as critical, requiring prompt intervention. Very low risk histories had a 0.0% incidence of critical port abnormalities in our cohort, regardless of imaging findings. Low risk histories had a 10.5% incidence of a critical abnormality and were best evaluated either by line injection, either directly or following an abnormal chest radiograph. Intermediate and high risk histories were associated with a 30.5% and 61.1% incidence of critical port abnormalities, respectively, and were best evaluated by line injection without preceding chest radiograph. Conclusions There are several scenarios in which imaging does not meaningfully affect management of malfunctioning central venous ports. Recognizing these inefficiencies may allow for more appropriate and cost-effective use of radiographs and line injections to evaluate the cause of port malfunction. © 2014, ASSOCIATION FOR VASCULAR ACCESS. Published by Elsevier Inc. All rights reserved.