Abstract: Technology described herein includes a method that includes providing, by an optical light source, a light beam configured to traverse an optical path through a fluid comprising the biological sample in a container. A length of the optical path through the fluid is between 3.3 mm to 5.5 mm, and a center of the light beam is at a height less than 1.6 mm from a bottom interior surface of the container, and a volume of the fluid is less than 120 ?L. An optical detector receives optical information after the light beam traverses the optical path. An output of the optical detector is associated with at least one parameter representing the one or more characteristics of the biological sample.