CPT® Code 83704

Lipoprotein, blood; quantitation of lipoprotein particle number(s) (eg, by nuclear magnetic resonance spectroscopy), includes lipoprotein particle subclass(es), when performed

The CPT® Code 83704 refers to a laboratory test that quantifies lipoprotein particle numbers in the blood, utilizing nuclear magnetic resonance (NMR) spectroscopy. Lipoproteins are complex biochemical structures composed of lipid molecules bound to proteins, playing a crucial role in the transport of fats throughout the body via the bloodstream. These lipoproteins vary in size and density, ranging from large, less dense particles, which contain more fat than protein, to smaller, denser particles, which have a higher protein content relative to fat. They can originate from dietary sources (exogenous) or be synthesized by the liver (endogenous). The test involves obtaining a blood sample through a procedure known as venipuncture, which is separately reportable. The process of quantifying lipoproteins can involve various techniques. For instance, CPT® Code 83700 describes a method where lipoproteins are separated using electrophoresis, a technique that employs an electrical field to segregate lipoprotein molecules, which are then stained and quantified. Alternatively, CPT® Code 83701 details a more advanced method involving high-resolution fractionation and quantitation of lipoproteins, which may include techniques such as quantitative electrophoresis or ultracentrifugation. In ultracentrifugation, lipoproteins are separated based on their hydrated densities, utilizing salts for fractionation, followed by centrifugation to distinguish between very low-density, low-density, and high-density lipoproteins, with subsequent quantification of each type. CPT® Code 83704 specifically highlights the use of NMR spectroscopy for the quantitation of lipoprotein particle numbers and subclasses. This sophisticated technique allows for the detection of lipoprotein particles of varying sizes, facilitating a detailed quantification of both the total number of lipoprotein particles and their subclasses. This information is particularly valuable in the assessment and management of patients with elevated triglyceride levels and in evaluating cardiovascular disease risk, especially in individuals with diabetes.