Insulin balls are subcutaneous induration caused by amyloid deposition due to repeated insulin injections to the same site, and subcutaneous injections in this area cause poor glycemic control. Therefore, it is important to assess the site for insulin balls and change the injection site at an early stage, but the assessment method remains unclear. Therefore, we aimed to clarify the available methods for insulin ball assessment. Using the scoping review method, we searched Japanese and English literature from January 1964 to November 2022 using the keywords "insulin ball" and "assessment" and included those that met the selection criteria. Database searches were conducted in Japan Abstracts Society, PubMed, Scopus, and CINAHL. The number of adopted studies regarding insulin ball assessment was 11. Palpation and visual examination were the assessment methods used in all studies. Blood tests and ultrasonography were both performed in nine articles, magnetic resonance imaging (MRI) was performed in five articles, and computed tomography (CT) was performed in four articles. There were two types of insulin balls: palpable and nonpalpable. A paper reporting that nonpalpable insulin balls can be detected by ultrasonography was noted. In addition to palpation and visual examination, imaging tests such as ultrasonography, MRI, and CT are necessary because some insulin balls cannot be palpated. This study suggested that incorporating ultrasonography in addition to palpation and visual examination may be useful as a screening tool for the early detection of insulin balls. We now need to validate the accuracy of the assessment by ultrasonography.
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