Check the APA Style blog for tips at
http://blog.apastyle.org/apastyle/2014/02/how-to-cite-a-psychological-test-in-apa-style.html
From a website
In-text citation
“In this study, we used Franzoi & Shields (1984) Body-Esteem Scale rather than the Cooper et al., (1987) Body Shape Questionnaire
Reference List
Franzoi, S. L. & Shields, S.A. (1984). The Body-Esteem Scale [Measurement instrument].
http://www.marquette.edu/psyc/facstaff_franzoi_scale.shtml
Format:
Author Surname, Initial(s). (Date). Title of Measurement [Format].URL