Understanding Your Blood Test Results
By Lauren Amphlett

If you’ve recently had a blood test in the NHS, you might be looking at a list of abbreviations and numbers that don’t make much sense to you. This article will help you understand some of the most common blood test results that you might see. However, it’s important to remember that this is a basic guide.

Liver Function Tests (LFTs)

Liver function tests are a group of tests that help to check how well your liver is working. Here are a few of the important ones:

ALT (Alanine Aminotransferase) and AST (Aspartate Aminotransferase): These enzymes are found inside liver cells. When the liver is damaged, these enzymes are released into the bloodstream. Higher than normal levels can indicate liver disease or damage.

ALP (Alkaline Phosphatase): This enzyme is found in the liver and bones. High levels can indicate liver disease or bone disorders.

Bilirubin: This is a waste product processed by the liver. High levels can indicate a problem with the liver or bile ducts.

Gamma GT (Gamma Glutamyl Transferase): This enzyme is often elevated in conditions that cause damage to the liver or bile ducts.

Albumin: This is a protein made by the liver, and it’s needed to maintain growth and repair tissues. Low levels can suggest a problem with the liver or kidneys.

Full Blood Count (FBC)

A full blood count measures different parts of your blood.

Haemoglobin (Hb): This is the substance in red blood cells that carries oxygen around the body. Low levels can suggest anaemia.

White Blood Cells (WBC): These are part of your immune system and help fight infections. High levels can indicate an infection, inflammation or an immune disorder. Low levels can suggest a weakened immune system.

White blood cells are further divided into different types, each with a different role:

  • Neutrophils: These cells are the most common type of white blood cell and are the first to respond to infections.
  • Lymphocytes: These cells are crucial to your immune system and play a key role in your body’s response to viruses.
  • Monocytes: These cells help to fight off bacteria.
  • Eosinophils: These cells help to fight off parasites and also play a role in allergies.
  • Basophils: These cells are involved in inflammatory reactions and allergies.

Platelets (Plt): These are small cells that help your blood to clot. High or low levels can indicate a range of conditions and can affect your blood’s ability to clot.

Urea & Electrolytes (U&Es)

This test checks kidney function by measuring levels of substances like sodium, potassium, and urea in your blood. Abnormal levels can indicate a problem with your kidneys or with your body’s fluid and electrolyte balance.

Sodium (Na+): Sodium is an electrolyte that helps maintain fluid balance in your body. Abnormal levels can indicate dehydration, kidney problems, or certain hormonal disorders.

Potassium (K+): Potassium is another important electrolyte that plays a crucial role in maintaining proper heart and muscle function. High or low levels of potassium can have various causes and may require medical attention.

Chloride (Cl-): Chloride is an electrolyte that works closely with sodium to maintain the balance of fluids in your body. Abnormal chloride levels may indicate kidney issues or certain metabolic conditions.

Bicarbonate (HCO3-): Bicarbonate is a chemical involved in regulating the acid-base balance in your body. Abnormal levels can be seen in conditions such as kidney disease or respiratory disorders.

Urea: Urea is a waste product formed in the liver from the breakdown of proteins. Its level in the blood can reflect kidney function, and elevated levels may indicate impaired kidney function or dehydration.

Creatinine: Creatinine is a waste product produced by muscles and excreted by the kidneys. It is commonly used to assess kidney function. High levels of creatinine may indicate reduced kidney function.

Estimated Glomerular Filtration Rate (eGFR): This is a calculated value based on creatinine levels that estimates how well your kidneys are filtering waste from your blood. A lower eGFR may indicate decreased kidney function.

Cholesterol

This test measures levels of different types of cholesterol and triglycerides in your blood, which can help to assess your risk of heart disease.

Total Cholesterol: This measures the total amount of cholesterol in your blood, including both high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol. It is an overall indicator of your cholesterol levels.

HDL Cholesterol: High-density lipoprotein cholesterol is often referred to as “good” cholesterol. It helps remove excess cholesterol from your blood and carries it to the liver for processing. Higher levels of HDL cholesterol are generally considered beneficial for heart health.

LDL Cholesterol: Low-density lipoprotein cholesterol is often called “bad” cholesterol. It contributes to the buildup of plaque in the arteries, increasing the risk of heart disease and stroke. Lower levels of LDL cholesterol are typically desirable.

Triglycerides: Triglycerides are a type of fat that circulates in your bloodstream. They are a source of energy for your body. High levels of triglycerides can be associated with an increased risk of heart disease, especially when combined with other risk factors.

Cholesterol Ratios: Cholesterol ratios provide additional insights into your cardiovascular health. The most commonly calculated ratios include:

  • Total Cholesterol/HDL Ratio: This ratio compares the total cholesterol level to the HDL cholesterol level. Lower ratios are generally considered better, as it indicates a higher proportion of “good” cholesterol to the total cholesterol.
  • LDL/HDL Ratio: This ratio compares the LDL cholesterol level to the HDL cholesterol level. Again, a lower ratio is typically preferable, as it suggests a lower risk of heart disease.

Clotting Tests

Prothrombin Time (PT) and International Normalised Ratio (INR): These tests measure how quickly your blood clots. They’re often used to monitor treatment with anticoagulants (blood-thinning medicines) like warfarin. A high INR or PT means that your blood is clotting more slowly than normal, which could increase the risk of bleeding.

Other Tests

C-Reactive Protein (CRP): This is a protein that rises in response to inflammation in the body. High levels can indicate an infection or a long-term disease such as rheumatoid arthritis or lupus.

Amylase: This is an enzyme that helps your body to digest food. High levels can indicate a problem with your pancreas, including conditions like pancreatitis.

D-Dimer: This is a protein fragment that is produced when a blood clot dissolves in your body. High levels can suggest that there might be significant clotting occurring in your body.

Blood Glucose: This test measures the amount of glucose (sugar) in your blood. High levels can indicate diabetes, while low levels can lead to hypoglycaemia (low blood sugar).

Thyroid Function Tests (TFTs): These tests measure how well your thyroid is working by checking levels of thyroid-stimulating hormone (TSH) and thyroxine (T4). Abnormal levels can indicate conditions like hypothyroidism or hyperthyroidism.

Conclusion

While this guide should give you a better understanding of your blood test results, it’s important to remember that these tests are just one part of the picture. Your GP or Specialist will interpret these results in the context of your symptoms, medical history, and other investigations. So if you have any questions or concerns about your results, don’t hesitate to ask your doctor or nurse for clarification. They are there to help you.

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