LDL cholesterol direct (LDL direct) in serum

Introduction

Used in conjunction with Synchron LX systems, Unicel DxC 600/800 systems.

Indications

hypertriglyceridemia

Principle

• direct quantification of LDL cholesterol in serum or plasma
• homogeneous assay, using detergent that solubilizes only non-LDL lipoproteins, releasing cholesterol & cholesterol esters to react with cholesterol esterase
• the result cholesterol is oxidized with cholesterol oxidase in a non-color forming reaction.
• a 2nd detergent solubilizes the remaining LDL lipoprotein, releasing cholesterol & cholesterol esters to react with cholesterol esterase
• the result cholesterol is oxidized with cholesterol oxidase in a reaction coupled to chromphore production
• timed endpoint method monitoring absorbance at 560 nm

Detergent 1
                    cholesterol esterase
HDL-C, VLDL-C, CM-C -------------------->   non color poduct
                    cholesterol oxidase

Detergent 2
                 cholesterol esterase
LDL cholesterol  -------------------->  cholestenone + H2O2
                 cholesterol oxidase

                        peroxidase
H2O2 + DSBmT* + 4-AA*   ------------>    color product

* DSBmT = N,N-bis (4-sulphobutyl)-m-toluidine-disodium 4-AA = 4 aminopyrine

Increases

• hyperlipoproteinemia type 2B

More general terms

• special chemistry test

Additional terms

• cholesterol in serum/plasma
• lipid panel (fasting lipid panel, FLP)