Blood test types for beginners; HEALTHMATTERS YOUR EDICAL QUERIES ANSWERED.

Byline: Dr Elena Douse

I AM always surprised by the number of patients who attend surgery for their blood results, not knowing what tests they've had done or why they were done in the first place.

Testing your blood can reveal a whole host of anomalies which may require treatment, as well as enabling us GPs to monitor any current treatment you may be receiving.

The range of blood tests available, as well as the abbreviated terms that doctors often use, can leave patients feeling confused and bewildered. Indeed, medical jargon can sometimes sound like a foreign language, so your doctor should take the time to explain the terminology and the significance of any abnormal results. The following is a quick summary of the more common blood tests.

FBC: Full Blood Count Probably the most commonly requested blood test, the FBC looks at haemaglobin levels (the red pigment in the blood) to assess whether you are anaemic. The FBC also tells doctors about the white blood cell count (the cells which fight infection) and the platelet count (the cells responsible for blood clotting).

U&E: Kidney Function Test Our kidneys are important for filtering toxins from the blood and also for regulating the blood salts sodium and potassium. These salts and toxins are measured in the U&E, and any abnormality in their levels can reflect deteriorating kidney function. Several medications, including some blood pressure tablets, can affect kidney function, and the U&Es are often checked following commencement of these treatments.

LFT: Liver Function Test As well as measuring the yellow pigment billirubin (responsible for a jaundiced appearance), the LFTs also monitor enzymes produced by the liver. An elevation in the liver enzymes may indicate damage to the liver matrix itself or may be an indication of gallstones or alcohol usage. Some medications, such as cholesterol-lowering drugs (statins), can also raise the liver enzymes, and the LFTs are regularly monitored in anyone taking these medications.

Glucose: Sugar Levels Usually done as a fasting blood test (patients are asked not to eat or drink anything from the night before), the glucose level indicates whether a patient is diabetic. A fasting level over seven is diagnostic of diabetes.

Lipid Profile: Cholesterol Levels Another fasting blood test, the lipid profile provides levels and ratios of good and bad cholesterol in the blood. Doctors are trying to reach target cholesterol levels of less than four, particularly in those patients who fall into high risk groups eg diabetics, stroke pa-tients and those patients suffering from coronary heart disease.

TFT: Thyroid Function Test Often done if patients are feeling tired, depressed or generally unwell, the TFTs will tell a doctor whether a patient has an underactive or overactive thyroid. Patients with established thyroid disease need regular TFTs to ensure they are receiving correct treatment doses.

CRP/ESR: Inflammatory Markers The inflammatory markers, C-Reactive Protein and Erythrocyte Sedimentation Rate, are usually requested for those patients suffering from joint or muscle pains. Many rheumatological conditions such as rheumatoid arthritis can cause elevated markers, and gives a doctor a good indication of the control of the condition. The CRP and ESR are very sensitive and will rise with any inflammation occurring in the body such as during infection, following surgery, or as a result of chronic illness.

PSA: Prostate Specific Antigen Only applicable to male patients, the PSA is requested if there is any suspicion of possible underlying prostate cancer. An elevated PSA level always requires further investigation.

Although the PSA is specific to the prostate, it is not just specific to prostate cancer, and may be raised for other, less serious, reasons such as a urinary tract infection or due to benign, age-related enlargement of the prostate.

So if you're due to have blood taken, make sure you know what's being done and why. Remember, it's your body and your blood, so don't be left in the dark!