At our private clinic in Harley Street, we see many patients who are being tested for blood cholesterol. People ask how do you know if you have high blood cholesterol? They also want to know what the symptoms and causes of a high blood cholesterol levels will be.
Diagnosis will start with a blood test. Depending on the type of blood you have there will be specific things you need to do, beforehand.
Before some blood tests you will be able to eat and drink. For ‘fasting’ blood tests you will not be able to eat or drink (apart from water) before your test. It is likely that you might be told not to have any alcohol and asked, as well, not to smoke before the test.
These are some of the test we carry out at Medical Express - our Private GP clinic in London.
Fasting blood glucose test
Nothing to eat and drink apart from water for 8 - 10 hours before a fasting test for blood glucose - used to diagnose diabetes.
Iron blood test
Blood sample taken before you eat anything in the morning. Avoid taking iron tablets for 24 hours before the test. The body absorbs iron quickly from pills or food and that could raise your iron levels affecting the test results. Iron blood tests diagnose conditions such as iron deficiency anaemia.
Tests for blood cholesterol levels
Usually nothing to eat and only water to drink for 9 to 12 hours before cholesterol tests. There are different tests for cholesterol that when done together are called a lipid profile that tests the levels of:
"Bad" (LDL) cholesterol
"Good cholesterol" (HDL)
Triglycerides (other fatty substances)
If you have only a triglycerides test, no alcohol should be taken for 24 hours before the test and you should fast.
Gamma-glutamyl transferase (GGT) test
This test is used to help diagnose liver disease. GGT levels may be affected by alcohol taken in the 24 hours preceding the test. Smoking can also affect test results.