A blood test can reveal numerous health aspects, including signs of infection or inflammation, how well organs like the kidneys and liver are working, blood sugar levels (diabetes risk), cholesterol and fats (heart health), anemia, and thyroid function, providing a comprehensive health snapshot for diagnosis, monitoring, and screening.
Blood tests can detect a vast range of health issues, from infections, anemia, and nutrient deficiencies to chronic conditions like diabetes, heart disease, and kidney/liver problems, helping doctors diagnose illnesses, monitor treatment effectiveness, assess organ function, screen for risks, and check for blood disorders or cancers. They measure various components like blood cells, proteins, enzymes, and electrolytes to provide insights into your overall health and specific bodily functions.
These are usually notes which the computer generates if a blood test result is abnormal, or out of 'normal range'. Understandably, this can make you feel worried. But you can be reassured that these flags will be reviewed by your GP or other health professional, who will let you know if there is a cause for concern.
5 Common Lab Tests and How To Read Them
A full blood count (FBC) checks red cells, white cells, and platelets. Low red cells or hemoglobin may indicate anemia, while high or low white cells can point to infection or immune problems. Platelet counts highlight whether your blood clots normally.
Blood tests can help to diagnose some heart conditions, including a heart attack, or check if you have a risk factor for one, such as high cholesterol levels. Find out why you might need a blood test and what happens when you have one.
The medical significance of a single result that is slightly high or slightly low may be difficult to determine. This is why a doctor may repeat a test, and why they may look at results from your previous tests. However, a result outside the reference range may indicate a problem and warrant further investigation.
A full blood count test looks at different cells in your blood. This can identify if you have anaemia, which is a lack of red blood cells carrying oxygen around the body. It can also help to rule out or confirm infections and viral conditions, such as myocarditis, which is when the heart muscle becomes inflamed.
Testing for an antibody deficiency (or humoral immune function) The standard screening tests for humoral immune function start with measuring immunoglobulin (Ig), or antibody, levels in the blood serum. These consist of IgG, IgA, IgM, and sometimes IgE levels. The results must be compared to age-matched controls.
Common lab tests include:
Complete blood count: Checks your overall health and is often given during the yearly checkup. Testing your red and white blood cell count can show if you have an infection (high white blood cell count) or anemia (low red blood cell count).
Two crucial symptoms you should never ignore are sudden, severe headaches (like "the worst headache of your life") and sudden weakness, numbness, or slurred speech on one side of the body, as these can signal a stroke or brain issue, requiring immediate medical help. Other critical signs include chest pain, shortness of breath, unexplained weight loss, and persistent confusion or changes in bowel habits, all pointing to potentially serious underlying conditions.
Results that lie outside the laboratory reference ranges are considered to be abnormal; however, various factors influence the tests.
Only around 1% of all musculoskeletal presentations in primary care will be due to serious pathology. Such pathologies include spinal infection, cauda equina, fracture, and malignancy. Vertebral fracture is the most common serious spinal pathology, followed by metastatic bone disease.
Most commonly detected viral antibodies are to:
If you've ever wondered if you might have a nutritional deficiency, you can now get tested at your convenience with Labcorp OnDemand's wide range of vitamin and mineral blood tests. Optimize your health and wellness by finding out what nutrients you might be lacking and taking steps to improve your nutrition.
Neurological disease such as stroke, motor neurone disease, Alzheimer's and multiple sclerosis aren't diagnosable from blood tests. Similarly, the diagnoses of depression, schizophrenia, ADHD and autism lack a specific blood diagnostic marker.
Five signs of a weak immune system include frequent infections, slow-healing wounds, persistent fatigue, ongoing digestive issues, and getting sick with things that last a long time, like a cold that lingers or severe infections requiring strong treatment. These indicate your body struggles to fight off pathogens or repair itself effectively.
Consuming adequate amounts of several vitamins and minerals—including vitamin A, vitamin C, vitamin D, vitamin E, selenium, and zinc—is important for proper immune function, and clinical deficiencies of these nutrients weaken immunity and can increase susceptibility to infections [2,4,5,8-10].
The cause is not fully understood, but in some cases it is thought that autoimmune diseases are triggered by exposure to microorganisms or other environmental causes, especially in people with a genetic predisposition to the disorder. A single organ or multiple organs and tissues may be affected.
The Role of Standard Blood Tests in Public Health
These tests help doctors detect common conditions like anaemia, infection, high cholesterol, liver dysfunction and signs of diabetes. They are essential for diagnosing acute symptoms and managing chronic illnesses.
One of the most comprehensive drug tests is the 12-panel drug test, which can screen for 12 different substances in the body. These include illicit drugs, such as marijuana, cocaine, and PCP, as well as prescription medications like opioids, benzodiazepines, and barbiturates.
In simple terms, an FBC is a blood test that checks the number and types of cells in your blood. It provides an overview of your red blood cells, white blood cells, and platelets to determine if everything looks normal or if something might need a closer look.
They help detect infections, assess organ function, and monitor chronic diseases such as diabetes and heart disease. Regular blood tests can serve as early warning systems, allowing healthcare providers to detect and address issues before they become serious.
Before a blood test, you should not eat, drink (except water), smoke, chew gum, or exercise, especially if fasting is required, as these can alter results. Avoid alcohol for at least 24 hours and stop certain medications only if your doctor advises, otherwise take them as usual with water. Don't fast longer than recommended (usually 8-16 hours) or shorter than advised, and always check specific instructions with your doctor or lab.
Stress hormones like cortisol and adrenaline are released by the body in response to stress or anxiety. These hormones can impact the levels of glucose, cholesterol, and other substances in the blood, which can in turn affect the results of blood tests.