Abstract: A profile analysis reaction pack and related apparatus are disclosed, along with a method for simultaneously mixing, heating and reacting selected test reagents with multiple dilutions of a sample of body fluid to obtain a profile of the physiological condition of a given organ system. Each pack takes the form of a laminated card having a relatively rigid flat panel of transparent material secured to an opaque resilient panel, the resilient panel being preformed to define a plurality of generally semi-cylindrical reaction chambers disposed between the respective panels. During a profile test procedure, a sample of the body fluid to be tested is withdrawn from a storage chamber in the same pack and each reaction chamber is then injected with a diluted portion of the sample fluid. Temperature control is achieved by bracing the rigid panel of the pack against a fixed heated platen and by contacting the generally semi-cylindrical wall portion of each reaction chamber with a movable heated platen.