Like the brown paper bag test, the blue vein test was a means of telling if one of African American decent was fair-skinned enough to interact in the upper classes of black society or pass to interact in white society. Basically, if the skin color was light enough to reveal the blue hue of the veins in the underside of the forearm, one could pass this test.
If he passes the blue vein test, he can get a job in the office.
