Blood tests 101

Blood tests are the most important tests for chronic lymphocytic leukaemia (CLL).

If CLL is suspected, you’ll have a set of tests to confirm the diagnosis.

The full blood count (FBC) is one of the key tests in the diagnostic process and is the first step. When a smear of blood is prepared in a laboratory and looked at through a microscope, CLL cells appear as small, dark purple or blue cells, some of which break easily when a microscope film is made – these abnormal cells are known as ‘smudge or smear cells’ and are a characteristic feature of CLL. A FBC alone and blood cell examination will not be enough to confirm a diagnosis and more specialist blood tests including immunophenotyping will also be needed.

Learn more about diagnosis here

Types of blood tests

Full blood count

A full blood count (FBC) measures the number of red cells, white cells and platelets in your blood.

  • Red cells carry oxygen around our bodies. Haemoglobin is the part of the cell that carries oxygen. If you have a low red cell count, your doctor might say you’re anaemic (pronounced a-nee-mic). This can make you feel tired, short of breath and dizzy.
  • White cells fight infections. There are several different types of white cells, including neutrophils and lymphocytes.
  • Platelets help clot the blood. Symptoms of a low platelet count include abnormal bleeding, such as bleeding gums and nosebleeds.


Flow cytometry is the technique used most for immunophenotyping. This specialist test can look for abnormal CLL cells in your blood or bone marrow and count how many abnormal cells there are. This test is needed to diagnose CLL effectively.

Urea and electrolytes

These blood tests show how well your kidneys are working. Waste chemicals called urea and creatinine are produced by the body. Our kidneys remove them from our blood and get rid of them in our urine.

Electrolytes are substances such as sodium, potassium, chloride and bicarbonate.

Liver function tests (LFTs)

Liver function tests (LFTs) check how well your liver is working. LFTs look for levels of enzymes and proteins made by the liver or which are cleared by the liver. They include:

  • alanine aminotransferase (ALT)
  • aspartate aminotransferase (AST)
  • alkaline phosphatase (ALP)
  • gamma-glutamyl transferase (Gamma GT)

They might be raised if you have a blockage in your liver or bile duct, or if you drink a lot of alcohol.

LFTs also look at the amount of bilirubin in the blood. This is a chemical in bile.

Bilirubin can be raised if you have a problem with your liver or gallbladder. Bilirubin can cause yellowing of your skin and eyes (jaundice).

LFTs also measure albumin. This is a protein in the blood that can be low in some types of cancer. You can also have low albumin if you’ve been eating small amounts and are malnourished.

Other blood tests

You might have other tests to check for a blood protein called beta 2 microglobulin or an anti-globulin test to check for certain antibodies.

All these tests will help with your diagnosis and to plan your treatment.


Common Blood Test Abbreviations

This list of blood test abbreviations isn’t exhaustive, but it does cover the letters seen most commonly on laboratory or medical requisition forms. If you’re ever confused or concerned, it’s best to consult with your GP or other suitable medical professional.

ALT – Alanine Transaminase (part of a liver function test)
ANA – Antinuclear Antibody (also part of a liver function test)
AST – Alanine Aminotransferase (another part of a liver function test)
BAC – Blood Alcohol Concentration/Content (tests for intoxication level)
BMP – Basic Metabolic Panel (a standard group of blood tests)
BNP – Beta Natriuretic Peptide (testing for congestive heart failure)
BUN – Blood Urea Nitrogen (part of kidney function test)
CA – Calcium (testing blood calcium levels)
CBC – Complete Blood Count (test red and white blood cells for overall health and to detect abnormalities)
CK – Creatine Phosphokinase (test for muscle damage)
CR – Creatinine (part of kidney function test)
ESR – Erythrocyte Sedimentation Rate (tests for inflammation)
HCT – Hematocrit (part of the standard CBC test; proportion of red blood cells)
HDL/LDL – High Density Lipoproteins/High Density Lipoproteins (testing for “good” and “bad” cholesterol)
INR – International Normalized Ratio (a blood clotting test)
K – Potassium (a test for potassium levels)
Mg – Magnesium (testing for magnesium levels)
Na – Sodium (testing for sodium levels in the blood)
PSA – Prostate Specific Antigen (prostate cancer test)
PT – Prothrombin Time (test blood clotting along with INR or international normalized ratio)
RBC – Red Blood Cell Count (part of the CBC test)
TPO – Thyroid Peroxidase Antibodies (test for antibodies to thyroid)
Trig – Triglygerides (a part of cholesterol test)
TSH – Thyroid Stimulating Hormone (one of the main tests of a thyroid test)
WBC – White Blood Cell Count (part of the CBC test)