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 Field Name  Data Description
Test Name  LDL (Low Density Lipids) Direct, Fasting
Code  Low Density Lipids LDL Direct Fasting., LDL Direct
CPT Code  83721
Last Modified  4/26/2018 1:45:00 PM
Test Name  LDL Direct.
Synonyms  Direct LDL,LDL Cholesterol, LDLC,Lithol,CH, Choles, Low Di, LDLDIR, Low-density Lipoprotein
Patient Preparation  Patients are not required to fast prior to blood collection. Nonfasting and fasting samples can be used. Nonfasting results are slightly lower than fasting results.
Spec. Requirements  Blood
Tube  Red, Gold, Lavender (EDTA), Or Green (Heparin)
Collection Volume  Red 4.0 mL, Gold 3.5 mL, Lavender (EDTA) 2.0 mL, Green (Heparin) 3.0-4.0 mL
Storage  Ambient, Refrigerated or Frozen 14 days
Routine TAT  
Days Test Performed  
Performed by BHS  None
See Availability  
Reference Lab  LabCorp of America
Reference Lab Code  120295 Low-density Lipoprotein Cholesterol (Direct)
Clinical Use  For the direct determination of LDL cholesterol in nonfasting patients or in patients whose fasting triglycerides are >400 mg/dL, where the estimation of LDL by calculation may not be possible or may lead to inaccuracies. LDL cholesterol measurement, in conjunction with other lipid measurements, has been shown to be useful in assessing the risk of coronary heart disease (CHD). The National Cholesterol Education Program (NCEP)1 has stated that LDL cholesterol should be the “key index” in determination of CHD risk. Laboratory estimation of LDL cholesterol is most commonly determined by the use of formulas, such as the Friedewald formula.2 Use of this formula is limited to fasting samples with triglycerides <400 mg/dL. Triglyceride values between 250−400 mg/dL may also be associated with errors in LDL cholesterol estimation by calculation which, in turn, can lead to misclassification of the patient in regard to the NCEP guidelines.3
Reference Range  
Critical Value  
Component  LDL
Reference Range  <= 139.0 mg/dl
Critical Value  
Testing Sample Type  Serum (Preferred) or Plasma
Min Lab Testing Volume  0.4 mL
Special Handling  Collection:Separate serum or plasma from cells within 45 minutes of collection.
Lab Notes  
Methodology  ENZ - Enzymatic
Limitations  Causes for Rejection: Use of anticoagulants containing citrate. NCEP guidelines for interpretation (see Reference Interval) are based on serum values, and when classifying patients, serum or serum equivalent values should be used. For this direct LDL method, a factor of 1.06 should be used to convert EDTA plasma values to serum values. There is no significant interference from hemolysis up to 10.0 g/L hemoglobin, from bilirubin up to 30 mg/dL, and from triglycerides up to 1200 mg/dL. Abnormal liver function affects lipid metabolism; consequently, HDL and LDL results may be of limited diagnostic value in patients with hepatic disorders.

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