THE PITTING TEST; AN INVESTIGATION OF AN UNSTANDARDIZED ASSESSMENT OF LYMPHEDEMA

Soft tissue pitting is the occurrence of a temporary indentation on the body surface after the release of sustained thumb or finger pressure. In the management of lymphedema, presence or absence of pitting can contribute to clinical reasoning and guide healthcare management. However, the pitting test and its application has not been described consistently nor is it a standardized part of assessment. Therefore investigations are needed to assess the outcome measures of pitting identification and characterization of lymphedematous tissue. To determine valid testing parameters for a future study, we evaluated six therapists of varying lymphedema experience who assessed a range of locations on six patients with lymphedema representing the breadth of pitting assessment techniques used clinically. The consequence of an unstandardized assessment is demonstrated by the large variation in techniques observed for test duration (1.1 to 76.0 seconds), pressure (1.3 to 14.4 N/cm2) and contact area (0.2 to 6.8 cm2). Experienced therapists performed the pitting test with a significantly different technique from their inexperienced counterparts, involving a longer duration (p < 0.001), higher pressure (p < 0.001) and a larger contact area (p < 0.001). The results of this pilot study support the need for evaluation of the underlying tissue response to sustained pressure and release, in order to inform the development of a standardized procedure.