Abstract: An improved method of recovering antihemophilic factor (AHF) from cryoprecipitated blood plasma is provided. The improved method incorporates the addition of a calcium ion source during the step of cold precipitation of fibrinogen and fibronectin contaminants, as well as the addition of polyethylene glycol (PEG) at one of various stages of the recovery process. PEG may be added during the cold precipitation of fibrinogen and fibronectin, during the precipitation of AHF, or prior to the filtration of AHF solution. The method of the present invention results in a final AHF product having greatly increased solubility, higher specific activity, and lower fibrinogen and fibronectin content.

Abstract: An assembly for identifying the results of a specimen analysis wherein such specimen analysis occurs in an array of discrete cells. The assembly includes a housing having top, bottom, end walls, and sidewalls. An array receiving recess is provided on the top wall for receiving and holding in a fixed position the array of the discrete cells. An ultrasonic signal producing stylus is provided for selectively producing an ultrasonic signal adjacent a cell in the array in which the results of the analysis are to be identified. A first ultrasonic signal transducer is provided on the top wall for converting the ultrasonic signal from the ultrasonic signal generator to a first electrical signal. A second ultrasonic signal transducer is provided on the top wall for converting the ultrasonic signal from the ultrasonic signal generator to a second electrical signal.

Abstract: Fluorogenic substrates for proteolytic enzymes having the formula: ##STR1## or acid salts thereof wherein: R.sub.1 is hydrogen-L, hydrogen-D, benzoyl, benzenesulfonyl, glutaryl, pyroglutamyl, carbobenzoxy, D-serine, or carbobenzoxy-serine;R.sub.2 is hydrogen, phenyl, a straight, branched or cyclic alkyl having 1 to 4 carbons, or propionic acid;R.sub.3 is hydrogen, straight or branched or cyclic alkyl having 1 to 4 carbons, 4-aminobutane, or 3-guanidylpropane;R.sub.4 is methyl, 4-aminobutane, or 3-guanidylpropane;R.sub.5 is a fluorogenic moiety, severable from said compound by a proteolytic enzyme and having different fluorescent property when severed from said compound than when forming part of said compound.The enzymes, when reacting with the substrate, remove the fluorogenic group R.sub.5 producing an increase in its fluorescence. The increase of the fluorescence is an indication of the activity of the enzyme present. Specific enzymes thusly detectable include plasmin, thrombin, the factors X.sub.a, XI.sub.