Patent ID: 9695464
Date: 2017-07-04
CPC Classifications: C12Q,G01N

Claim:
1. An enzymatic method not requiring a high density lipoprotein (HDL) calibration standard for measuring the concentration of cholesterol, associated with a high density lipoprotein (HDL) component in a plasma portion of a blood-cell containing sample, wherein the sample contains both a HDL component and a non-HDL component, which also comprises cholesterol, wherein the HDL component is a component devoid of apolipoprotein B, and wherein the non-HDL component is a component containing apolipoprotein B in the plasma portion of the blood-cell containing sample, the method comprising the steps of: i) diluting the sample; ii) substantially removing blood cells to provide a substantially cell free sample; iii) contacting the sample with a blocking reagent for the non-HDL component such that access to cholesterol from the non-HDL component is temporarily blocked while cholesterol from the HDL component remains accessible to a cholesterol converting enzyme; iv) contacting the sample with at least one converting enzyme that reacts specifically with the cholesterol associated with the HDL and generates one or more detectable reaction product(s); v) monitoring the detectable reaction product(s); vi) relating an amount of the detectable product(s) to the concentration of the cholesterol associated with the HDL component in the blood sample, wherein the concentration of the cholesterol associated with the HDL component is related to the amount of the corresponding detectable reaction product(s) by means of estimating an un-measurable (fictive) endpoint for the concentration of the HDL-associated cholesterol by an algorithm; wherein step iii) may be carried out at any stage up to and including step iv) but before steps v) or vi) and wherein the blocking reagent of step iii) may be added to the sample separately or in step i) or step iv), and wherein steps i) and iii) are carried out before step ii).