Cholesterol, LDL (LDL-C), Plasma 

 

Specimen requirement

Adult patient:

 

  Heparin gel tube

 

Minimum blood volume: 5 mL

Paediatric patient:

 

Paediatric heparin tube

 

Number of vials: 1

 

Minimum blood volume: 1.3 mL

Authorisation code required

No

24 Hr available service

Yes

 

(Call extension: 3353 for express result)

Method

Spectrophotometry

Reference interval

Plasma:


For adults (≥ 18 years):

Desirable levels:

  Fasting Non-fasting
Cholesterol < 5.0 < 5.0
HDL Cholesterol > 1.0 > 1.0
Triglycerides < 1.7 < 2.0
LDL Cholesterol < 3.0 < 3.0
Non HDL Cholesterol < 3.8 < 3.9

Treatment goals based on total cardiovascular disease risk assessment:

  Moderate High Very High
LDL Cholesterol < 3.0 < 2.5 < 1.8
Non HDL Cholesterol < 3.8 < 3.3 < 2.6

The reference intervals were adopted from ESC/EAS/EFLC 2016 (Eur Heart J. 2016:37:1944-58. 2999-3058)

For paediatric patients (<18 years):

  Low Borderline Low Acceptable Borderline High High
Cholesterol     < 4.4 4.4 - 5.1 ≥ 5.2
HDL Cholesterol < 1.0 1.0 - 1.2 > 1.2    
Triglycerides (0 - 9 years)     < 0.8 0.8 - 1.1 > 1.1
Triglycerides (10 -18 years)     < 1.0 1.0 - 1.5 > 1.5
LDL Cholesterol     < 2.8 2.8 - 3.3 ≥ 3.4
Non HDL Cholesterol     < 3.1 3.1 - 3.7 > 3.7

The reference intervals were adopted from NCEP/NHLBI 2011 (Pediatrics. 2011:128 Suppl 5:S213-256)

Clinical indication

Assessment of lipid status, particularly as a risk factor for coronary artery disease and in diagnosis and treatment of disorders involving elevated cholesterol as well as lipid and lipoprotein metabolic disorders.

 

To assess atherosclerotic risk, cholesterol should be performed with triglyceride and HDL assays, as part of a global risk assessment.

 

LDL cholesterol is often calculated rather than measured directly although this method is unreliable if levels of triglyceride are > 4.5 mmol/L.  Thus, when triglyceride > 4.5 mmol/L, LDL cholesterol would not be calculated. Direct LDL cholesterol will be measured if total cholesterol = / > 5.2 mmol/L

Result interpretation

High LDL and low HDL levels are associated with a significantly increased risk of coronary artery disease in all age groups. The cause may be primary (familial hypercholesterolaemia and other genetic disorders) or secondary (associated with e.g. biliary obstruction, hypothyroidism, nephrotic syndrome).

 

Levels are reduced for up to 8 weeks with acute illness (e.g. myocardial infarction, acute infection) and assessment should not be attempted during this time.

Measurement of uncertainty

See table.

Frequency of measurement

Daily