Which sequence correctly describes the four steps of Beta Quantification?

Which sequence correctly describes the four steps of Beta Quantification?

• A. Ultracentrifugation to remove CM and VLDL; Measure cholesterol of the supernatant; Precipitation to remove LDL; Measure again cholesterol of the supernatant; Difference between the 1st and 2nd calculation is LDL
• B. Precipitation to remove LDL; Ultracentrifugation to remove CM and VLDL; Measure cholesterol of the supernatant; Measure again cholesterol of the supernatant; Difference equals LDL
• C. Ultracentrifugation to remove CM and VLDL; Precipitation to remove LDL; Measure cholesterol of the supernatant; Measure again cholesterol of the supernatant; Difference equals LDL
• D. Measure cholesterol of the supernatant; Ultracentrifugation to remove CM and VLDL; Precipitation to remove LDL; Measure again cholesterol of the supernatant; Difference equals LDL

Answer: (A)

The method tests how LDL cholesterol is quantified by comparing two measurements after removing interfering lipoproteins. Start by using ultracentrifugation to clear chylomicrons and VLDL, which have lower density and would otherwise contaminate the LDL reading. Then measure the cholesterol in the remaining supernatant, which contains LDL and HDL. Next, precipitate the LDL (the beta-lipoproteins) so only HDL remains in solution, and measure the cholesterol again. The LDL value comes from the difference between the first reading (LDL plus HDL) and the second reading (HDL alone). This sequence precisely isolates LDL by sequentially removing the interfering particles and then LDL itself, allowing the HDL measurement to be subtracted from the total to yield LDL.

The method tests how LDL cholesterol is quantified by comparing two measurements after removing interfering lipoproteins. Start by using ultracentrifugation to clear chylomicrons and VLDL, which have lower density and would otherwise contaminate the LDL reading. Then measure the cholesterol in the remaining supernatant, which contains LDL and HDL. Next, precipitate the LDL (the beta-lipoproteins) so only HDL remains in solution, and measure the cholesterol again. The LDL value comes from the difference between the first reading (LDL plus HDL) and the second reading (HDL alone). This sequence precisely isolates LDL by sequentially removing the interfering particles and then LDL itself, allowing the HDL measurement to be subtracted from the total to yield LDL.