Measuring Limb Volume: Accuracy and Reliability of Tape Measurement Versus Perometer Measurement.

BACKGROUND: Accurate limb volume measurement is key in the assessment of outcomes in lymphedema microsurgery. There are two commonly used methods as follows: manual circumferential measurement (tape) or Perometer measurement. There are no data on the intra- and interclass correlation of either method, making it difficult to establish a gold standard of limb volume measurement. We aim to assess the intra- and interclass correlation of each method to establish the most appropriate method for clinical practice and future research studies, aiming to compare the accuracy and reliability of tape measurement as assessed against Perometer measurement. METHODS AND RESULTS: Student volunteers and experts (lymphedema practitioners) were each asked to perform repeat tape and Perometer measurements on the upper or lower limb of one healthy volunteer. Perometer measurements were globally more accurate than tape (average SE [Perometer]: 23.23 vs. 77.21 [tape]). For intraobserver reliability, experts outperformed students in all domains tested, with little difference in intraobserver reliability using tape or Perometer (average Cronbach's alpha 0.9597 [expert)] vs. 0.6033 [student]). CONCLUSIONS: We recommend that, for increased interobserver reliability, the Perometer provides a more reliable standard of limb volume measurement.