Sensitivity and specificity of the blankenship FCE system's indicators of submaximal effort.

STUDY DESIGN

Single-blinded, randomized, posttest only design.

OBJECTIVE

To help contribute to the body of evidence in defining the validity of functional capacity evaluations.

BACKGROUND

Functional capacity evaluations (FCEs) are tests used to help determine an individual's readiness to return to work. Most FCEs incorporate indicators of effort within the evaluation. Published evidence validating the use of these indicators is limited.

METHODS AND MEASURES

Forty-nine injured and noninjured individuals 18 to 65 years of age participated in this study. The participants were randomly assigned to 1 of 2 groups: 100% effort or 50% effort. Raters were blinded to participant group. The Blankenship Version 6.0 software was used to analyze the data and a Blankenship FCE validity profile was scored. A score of 70% or greater was deemed a valid FCE as adopted by the Blankenship protocol.

RESULTS

The sensitivity of the FCE components tested was demonstrated to be 80% and specificity was 84.2%. The positive likelihood ratio was 5 and the negative likelihood ratio was 0.2. A receiver operating characteristic (ROC) curve demonstrated the 70% cut-off value for scoring the FCE was optimal.

CONCLUSION

Four components of the Blankenship FCE system demonstrated good sensitivity and specificity for detecting submaximal effort. However, clinicians should note that false positives (maximum effort identified as submaximal effort) may occur and scores of "equivocal" are not scored in the "criteria passed" category. The rater should be aware that this method of scoring could potentially influence a client's overall FCE score.