Within the profession of sonography, credentialing is the process through which a sonographer completes educational and training prerequisites, followed by a proctored examination. Upon successful completion of this process, a credential (an attestation of qualification) is awarded by a certifying organization. A credential provides sonographers with titles such as Registered Diagnostic Medical Sonographer, Registered Diagnostic Cardiac Sonographer, Registered Cardiac Sonographer, Advanced Cardiac Sonographer, and others. The process of credentialing differs from that of physician credentialing, for example, which involves demonstration of training and competence in application for hospital privileges. Credentialing of sonographers has helped define sonography as a recognized allied health profession, distinct from other medical technologies. In cardiac ultrasound, employment often requires a credential or a commitment to obtain a credential shortly after hiring. The American Society of Echocardiography has been a strong advocate of the value of credentialing of cardiovascular sonographers. A sonographer who is credentialed, and who might also work in an accredited laboratory, demonstrates evidence of acknowledged accomplishment and performance that is welcomed by consumers and professionals. It is recognized that a credential, based on the demonstration of qualifications and psychometrically sound examinations, is only as valuable as the evaluation and examination process. Most members of the American Society of Echocardiography would agree that credentialing of sonographers is associated with increased quality of ultrasound examinations and sonographer performance. But where is the evidence to support this belief?

In this issue of JASE , a single-author report by Bremer describes an evaluation of the Intersocietal Accreditation Commission (IAC) Echocardiography database, based on review of case studies submitted for the IAC Echocardiography laboratory accreditation process. The aim of the study was to determine the relationship of sonographer credentialing status to clinical competence, defined by echocardiographic image quality of the submitted echocardiographic cases. Adult cases of aortic stenosis and regional left ventricular dysfunction were evaluated by sonographers trained in the assessment of image acquisition and quality, using an image quality score (IQS). The IQS was considered a measure of clinical performance. The status of the personnel (credentialed or not) and echocardiographic laboratory features were also abstracted from the IAC database.

Bremer reports that compared with noncredentialed sonographers, credentialed individuals achieved higher scores in nearly all components of the IQS. The report is unique in assessing the performance of sonographers involved in the process of laboratory accreditation, and it uses a measure of performance based on independent review of case studies. An important aspect of Bremer’s study is that it included large numbers of credentialed and noncredentialed sonographers. It builds also on a recent publication by Nagueh et al . that used the IAC database to determine factors associated with success or failure in achieving laboratory accreditation. Although the results of these two studies provide evidence that credentialing is associated with improved echocardiographic performance, some caution in extrapolating the findings of these studies is prudent, because of limitations inherent in any database and retrospective review of submitted echocardiographic case studies.

The large difference in the number of noncredentialed (>1,100) and credentialed (>6,100) sonographers in Bremer’s study should be noted. This difference could introduce bias in the overall analysis, but it was not possible to compare two groups with similar numbers of sonographers. Differences in point of care (hospital based vs office based or mobile) could also have been associated with differences in the quality of submitted examinations performed by sonographers.

It is challenging to devise a metric that reflects all aspects of the echocardiographic evaluation of cardiovascular disease processes. It is possible that the inclusion of more examination variables in the IQS could have separated further the differences in performance between noncredentialed and credentialed sonographers. Although the IQS may well contain some subjectivity, its assessment by experienced cardiac sonographers, who have both clinical experience and training in assessment of submitted case studies, and Bremer’s effort to demonstrate reproducibility in the IQS assessment, does support the potential use of an IQS as an indicator of examination performance and quality.

One limitation of the IAC database is the use of laboratory procedure volume as a metric for experience, because years of sonographer experience was not available. One might expect that actual years performing sonography could well have widened the difference in performance between groups. It is important to note that credentialing is a measure of entry-level performance, and experience should build on that. Although review of submitted cases may identify examinations of high quality, it is possible that laboratories successful in IAC accreditation are more likely to employ sonographers who are more skilled at selecting cases for submission, or who possess greater experience in the accreditation process and are aware of what the reviewers are looking for. A prior investigation revealed that 75% of applications submitted were for reaccreditation and that laboratories granted accreditation more often employed credentialed sonographers. The IAC database could be expanded to include information on the educational background of sonographers, such as those who have completed accredited degree programs or those who have qualified for a credentialing examination on the basis of on-the-job training. Finally, it is not known if the age of ultrasound equipment used to acquire the submitted images may have affected image quality, although this seems an appropriate question to ask.

The use of a credentialing examination as a measure of quality has a limitation in that current examinations are largely knowledge based. In early years, some credentialing examinations included an actual assessment of live scanning performance. For a variety of reasons, testing of performance during live scanning is no longer feasible. Efforts are ongoing within the credentialing organizations to include examination elements that test actual scanning ability, in addition to knowledge. This might provide an additional method to assess a sonographer’s technical skill in acquiring high-quality echocardiographic images.

Bremer’s report addresses a topic of interest regarding cardiovascular sonographers’ role in the process of achieving accreditation, a topic of relevance to readers of this journal. The publication also reveals areas in which further details could facilitate more robust future assessments of quality and performance, suggesting a need for expansion of the IAC database demographics. Investigation also could be extended to include evaluation of different disease processes and patients with congenital heart disease. The IAC database appears to be a valuable resource for further echocardiography research into the value of credentialing of cardiac sonographers.