A specimen collecting, processing and analytical assembly, designed for testing small volumes of body fluids, substances and secretions, said assembly comprising a one piece barrel assembly with a volumetrically graduated capillary tube having an open end, and optionally coated internally with an anticoagulant, a stabilizer or a preservative. The barrel assembly includes a filter membrane fitted above the capillary end at the junction of the barrel assembly and the capillary tube, a support means at the barrel's second open end, and an analytical testing means disposed there between. The invention also provides a sealed vial containing an analytical testing reagent, the vial being substantially airtight and sealed with a pierceable material, a first tip cap for closing the open end of the capillary tube, a second cap to close sealably the second open end of the barrel container and a lancet to induce capillary skin punctures.