Abstract: The present invention provides a process for the specific determination of the cholesterol of the HDL fraction in the presence of the LDL fraction of serum lipoproteins. Pancreatic cholesterol esterase is used to liberate cholesterol, and the liberated cholesterol then reacts with cholesterol oxidase and oxygen to form hydrogen peroxide. The kinetics of either of hydrogen peroxide formation or oxygen consumption is measured within 2 to 15 minutes after the start of the reaction between cholesterol and the oxidase. The temperature is maintained within a range of 20.degree. C., during a predetermined time interval. Specific concentrations of reactants are maintained in the reaction solution, i.e., from 0.05 to 30 U/ml pancreatic cholesterol esterase; from 0.1 to 50 U/ml cholesterol oxidase; from 1.0 to 20 mMole/liter of a tenside of the bile acid group, and 0.1 to 10 g/liter of a non-ionic detergent. The pH is kept within a range of 5 to 9.

Abstract: The present invention provides a process for the specific determination of HDL cholesterol in serum or plasma by incubation with a cholesterol detection system, containing cholesterol oxidase and cholesterol esterase in a buffered aqueous medium, and measurement of a product of the cholesterol oxidase reaction or of the oxygen consumption, wherein a sample to be tested is incubated in the presence of a salt of a bile acid or of a bile acid derivative or of dioctylsulphosuccinate, a first measurement is then carried out, subsequently a non-ionic, polyethylene oxide group-containing detergent or a secondary alkane sulphonate is added, again incubated and a second measurement is carried out, the amount of HDL cholesterol being determined from the difference between the first and second measurement.

Abstract: The present invention provides a creatinine antibody and a process for the preparation thereof, wherein a conjugate of creatinine and a material suitable for antiserum formation, which are connected via an aliphatic or araliphatic carboxylic acid as bridge member, is used as immunogen for antiserum formation.The present invention is also concerned with the use of the above antibody for the immunological determination of creatinine, wherein the antibody is incubated with a creatinine-containing sample solution, reacted with a conjugate of creatinine with a hapten carrier substance, whereby one of the components, antibody and conjugate, is present in the solid phase or in dissolved form and the other component is present in dissolved form and the inhibition of the binding reaction between the antibody and the creatinine conjugate is measured.

Abstract: The present invention provides a process for the immunological determination of creatinine, wherein creatinine is converted into 1-methylhydantoin, the 1-methylhydantoin formed is incubated in an aqueous medium with antibodies which are directed against a conjugate of a first hydantoin derivative of the general formula: ##STR1## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4, which can be the same or different, are hydrogen atoms, alkyl radicals containing up to 3 carbon atoms or phenyl radicals, with a first hapten carrier substance suitable for antibody formation, reacted with a conjugate of a second hydantoin derivative of general formula (I) with a second hapten carrier substance, one of the components antibody and conjugate being present in the solid phase or in dissolved form and the other component being present in dissolved form, and the inhibition of the binding reaction between the antibodies and the hydantoin conjugate with the second hapten carrier substance is measured.

Abstract: The present invention provides a creatinine antibody and a process for the preparation thereof, wherein a conjugate of creatinine and a material suitable for antiserum formation, which are connected via an aliphatic or araliphatic carboxylic acid as bridge member, is used as immunogen for antiserum formation.The present invention is also concerned with the use of the above antibody for the immunological determination of creatinine, wherein the antibody is incubated with a creatinine-containing sample solution, reacted with a conjugate of creatinine with a hapten carrier substance, whereby one of the components, antibody and conjugate, is present in the solid phase or in dissolved form and the other component is present in dissolved form and the inhibition of the binding reaction between the antibody and the creatinine conjugate is measured.