Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Beta quantification is regarded as a reference method for the measurement of LDL cholesterol and cholesterol concentrations in other lipoprotein fractions. The Newcastle beta quantification method is a simplified version of the CDC reference method, suitable for routine use. The method consists of an ultracentrifugation step to allow fractionation of lipoprotein classes and lipoprotein electrophoresis is applied to the total plasma and supernatant to improve the characterisation of the lipoprotein phenotype. Beta quantification allows direct measurement of LDL cholesterol and is not affected by high triglyceride concentrations. This makes the method useful for measuring LDL cholesterol when calculations used to estimate LDL cholesterol are not valid (triglycerides greater than 4.5 mmol/L in the case of the Friedewald equation). Beta quantification is also useful in the investigation of mixed hyperlipidaemia, particularly in the diagnosis of familial dysbetalipoproteinaemia (FDBL – aka remnant/type III hyperlipoproteinaemia). FDBL is usually associated with the apo E 2/2 genotype. However, the apo E 2/2 genotype is common (~1% of the population) and penetrance is low. Also, around 10% of cases of FDBL are due to mutations other than the usual E 2/2 genotype and these autosomal dominant mutations are not detected during routine APOE genotype analysis. Beta quantification confirms that the FDBL phenotype is present through identification of beta-migrating VLDL and a raised VLDL-cholesterol to triglyceride ratio.
Specimen container paediatric:
EDTA – Purple
Specimen container adult:
EDTA – Purple
Minimum volume paediatric:
1.5ml Plasma
Minimum volume adult:
1.5ml Plasma
Special requirements:
Take sample after a 12-14 hour overnight fast. Avoid freezing sample as freeze/thawing the sample can affect lipoprotein electrophoresis.
Sample stability:
Unseparated: 3 Days
Separated: 7 days at 4-8°C, do not freeze
Interpretation:
An interpretive comment is included with each report.
Reference ranges:
An interpretive comment is included with each report.
Factors affecting result:
Gross haemolysis or icterus may intefere with cholesterol/triglyceride measurement.