The invention features a single tool for collecting a known volume of a fluid biological sample from an animal, such as a human or small mammal, for mixing the sample with a predetermined amount of a reagent or a diluent, physically separate components of the sample, for storing the sample in a secure and stable fashion, and for then recovering some or all of the sample in a condition suitable for performing a diagnostic assay. The tool can be equipped with an optional means of recording or displaying information about the sample, such as a tag, a bar code, or a surface indicator that identifies, e.g., the date, animal number, and any additional information necessary. A second bar coded label to remove and attaché to the cage shall be provided. The cage/blood-sample can be correlated if needed at a later date.