Gouttebarge V, Wind H, Kuijer PP, Sluiter JK, Frings-Dresen MH. Reliability and agreement of 5 Ergo-Kit functional capacity evaluation lifting tests in subjects with low back pain. Objective To assess interrater reliability and agreement of 5 Ergo-Kit functional capacity evaluation lifting tests in subjects with low back pain (LBP). Design Within-subjects design, with 2 repeated measurements. Setting Academic medical center in The Netherlands. Participants Twenty-four subjects (10 men, 14 women) with LBP. Interventions Not applicable. Main Outcome Measure Five Ergo-Kit lifting tests (2 isometric, 3 dynamic) were assessed on 2 occasions (t1, t2), by 2 different raters (R1, R2). The interval between the test sessions was 3 days. Interrater reliability level was expressed with the intraclass correlation coefficient (ICC), and the level of agreement between raters with the standard error (SE) of measurement. Results ICCs means (reliability) of isometric and dynamic Ergo-Kit lifting tests ranged from .94 to .97, and SE of measurement values (agreement) ranged from 1.9 to 8.6kg. Conclusions There was good reliability and agreement between raters of the isometric and dynamic Ergo-Kit lifting tests in subjects with LBP, which supports the use of these tests to assess functional lifting capacity.