Polygenic Hypercholesterolemia Workup

Updated: Jan 20, 2017
  • Author: Catherine Anastasopoulou, MD, PhD, FACE; Chief Editor: George T Griffing, MD  more...
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Workup

Laboratory Studies

The US National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) suggests screening asymptomatic individuals aged 20 years or older with a fasting lipid panel every 5 years.

Based on US preventive screening taskforce (USPTF) 2014 recommendation, level A recommendations include screening men older than 35 years and women older than 45 years with risk factors. Level B recommendations include screening men aged 20-35 years with risk factors and women aged 20-45 years with risk factors. The risk factors include any one of the following:

  • Diabetes

  • Previous personal history of CHD or noncoronary atherosclerosis (eg, abdominal aortic aneurysm, peripheral artery disease, carotid artery stenosis)

  • Family history of cardiovascular disease in male relatives younger than 50 years or in female relatives younger than age 60 years

  • Tobacco use

  • Hypertension

  • Obesity (BMI ≥30)

Practically speaking, performing a risk factor analysis prior to obtaining screening blood test results is preferable. Patients can have risk factors for coronary heart disease (CHD) other than low-density lipoprotein cholesterol (LDL-C; see Causes). A full lipid profile is obtained after the patient fasts for 9-12 hours. Chylomicrons must be absent and the total triglyceride level must be less than 400 mg/dL in order to use the Friedewald formula to calculate LDL-C. The Friedewald formula is LDL-C = total cholesterol - high-density lipoprotein cholesterol (HDL-C) - triglycerides/5. Direct LDL-C measurements do not offer any greater use, except in patients with marked hypertriglyceridemia. Direct LDL-C measurements can be performed while the patient is in the nonfasting state.

To perform a careful medical evaluation, the practitioner must ascertain all medication intake (both prescription and over-the-counter medications) and perform tests of serum thyroid-stimulating hormone, liver function, creatinine, and urinalysis to rule out secondary dyslipidemias.