A standard media suspension body (150) for verification and calibration of an optical particulate measurement instrument and configured to be at least partially immersed in a sample fluid is provided according to the invention. The body (150) includes a substantially solid outer surface including a first end (151) and a second end (152) disposed along an axis of illumination A and at least one outer surface (153). The first end (151) is configured to admit impinging light. The suspension body further includes an inner volume. At least a portion of the inner volume includes a substantially suspended light scattering material (155) that is configured to scatter a predetermined quantum of the admitted light. The suspension body (150) further includes an end cap (156) formed on the second end (152) and comprising a light absorbing material. Light exiting the second end (152) is substantially absorbed by the end cap (156).