Abstract: Methods and devices for collecting at least two separate samples of a body fluid (e.g., blood) simultaneously. The device is introduced into a body of a living being whose blood is to be analyzed at a preexisting accessible cavity of the body which at least temporarily contains blood of the living being. The device has an interior having first and second hollow retaining compartments capable of receiving and holding the blood which is present in the cavity when the entire device is introduced into and remains wholly within the cavity. After the device is removed from the body cavity, blood is removed from the first and second hollow retaining compartments, such that the blood can be simultaneously separately collected and prepared for subsequent separate and different analyses. The first and second hollow retaining compartments are adapted to collect blood having similar characteristics. In a preferred embodiment, the first and second retaining compartments each contain an absorbent medium such as a sponge.