Preferred Sample Type

LDL Cholesterol (calculated)

Suitable Specimen Types

  • Serum
  • EDTA Plasma
  • Li Hep Plasma
5 - 10ml whole blood

Sample Processing in Laboratory


Sample Preparation

Centrifuge specimens

Turnaround Time

1 day

Sample Stability


LDL Cholesterol (calculated)

General Information

LDL is a type of lipoprotein that carries cholesterol in the blood. LDL is considered to be undesirable because it deposits excess cholesterol in the walls of blood vessels and contributes to 'hardening of the arteries' and heart disease. Hence LDL cholesterol is often termed 'bad' cholesterol. LDL levels are requested as part a lipid profile, along with total cholesterol, HDL, and triglycerides. LDL is calculated from the results of the triglyceride, total cholesterol and HDL results.

Patient Preparation

Ideally fasting specimen (12 hour fast)


LDL cholesterol concentration is estimated from the concentrations of Total Cholesterol (TC), HDL Cholesterol and Triglycerides (TG) using the Friedewald equation.

LDL cholesterol = TC- HDL - (TG/2.2)

The Friedewald equation should not be used under the following circumstances: when chylomicrons are present; when plasma triglyceride concentration exceeds 4.52 mmol/L; in patients with dysbetalipoproteinemia.

Reference Range

Less than 3.3 mmol/L


  • EQA Scheme?: Yes
  • EQA Status: NEQAS

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Protection of Personal Information – Laboratory Medicine comply with the Trust Data Protection Policy and have procedures in place to allow the Directorate and it’s employees to comply with the Data Protection Act 1998 and associated best practice and guidance.

The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database
Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235