Total cholesterol

Most UK laboratories print an upper limit of 5.0 mmol/L for the general population; some print no range at all and leave the figure to be read alongside HDL, LDL and non-HDL cholesterol. Fasting is not required.

Cholesterol is a waxy fat that the body needs to build cell walls and to make some hormones and bile. It travels in the blood inside particles called lipoproteins. Total cholesterol is the sum of the cholesterol carried in all of those particles, the ones often called 'good' (HDL) and 'bad' (LDL) added together.

Doctors request it as part of a lipid profile when looking at heart and circulation health, and to follow the effect of changes in diet, exercise and cholesterol-lowering medicines over time. It is also part of many routine health checks.

• A diet high in saturated fat
• Family patterns of high cholesterol, such as familial hypercholesterolaemia
• An underactive thyroid
• Kidney disease with protein loss in the urine, and some liver conditions
• Pregnancy
• Some medicines, including steroids and some water tablets

• Cholesterol-lowering medicines such as statins
• Weight loss and changes in diet
• An overactive thyroid
• Long-term illness, poor nutrition and some cancers
• The weeks after a heart attack, major surgery or a serious infection

• It sits a little higher in winter than in summer
• It falls for several weeks after any acute illness, so a value taken then can read lower than usual
• Different laboratory methods give slightly different figures

Fasting is no longer needed for cholesterol tests in the UK. A single value is read alongside HDL, LDL, non-HDL cholesterol and triglycerides, and the trend over time matters more than one result.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.