A new device to measure upper limb circumferences: validity and reliability.

Aim: The aim of this paper was to examine the reliability and validity of a new measurement device that counters the disadvantages of the traditional method of arm circumference measurements.

Methods: We measured the arm on the non-operated side of breast cancer patients. Sixty-four patients were measured twice by the same assessor and 48 patients were measured twice by two different assessors. The arm circumferences were measured at the olecranon and each 4 cm proximal and distal of the olecranon. The measurements were performed with a self-developed device consisting of a stainless steel bar on which a tapeline was fixed at every 4 cm distance. The arm volume was calculated from the circumference measurements with the frustrum formula and was also measured directly with the water displacement method.

Results: For the circumference measurements, intrarater and interrater ICCs ranged between 0.942 and 0.998. ICCs for the calculated arm volume were also very high. No systematic changes between the first to the second assessment could be found. The standard error of measurement for the circumference measurements as well as for the calculated arm volume was low (between 0.8% and 2.0%). An increase of 1.0 cm or more of the arm circumference at any measurement side and of 55 ml or more of the calculated arm volume was clinically significant.

Conclusion: Arm circumferences and also the calculated arm volume can be measured quickly and accurately with a simple and inexpensive device.