Blood Work: Stroke Diagnosis And Treatment

While blood tests are crucial in determining the cause of a stroke, they cannot be used to diagnose a stroke. When a stroke is suspected, doctors will first use imaging tests such as CT scans or MRIs to determine if there is damage or bleeding in the brain. Following this, blood tests are used to rule out other factors that can cause stroke-like symptoms, pinpoint a trigger for the stroke, and determine the best treatment.

Complete blood count (CBC) test

A complete blood count (CBC) is a group of blood tests that measure the number and size of the different cells in your blood. A CBC can be used to monitor and diagnose medical conditions and check on the health of your immune system.

A CBC measures:

• Red blood cells, which carry oxygen from your lungs to the rest of your body.
• White blood cells, which fight infections and other diseases. A CBC test measures the total number of white cells in your blood. A different test called a CBC with differential measures the number of each type of white blood cell.
• Platelets, which stop bleeding by helping your blood to clot.
• Haemoglobin, an iron-rich protein in red blood cells that carries oxygen from your lungs to the rest of your body.
• Hematocrit, the amount of whole blood that is made up of red blood cells.
• Mean corpuscular volume (MCV), the average size of your red blood cells.

A CBC can be used to help diagnose blood diseases, infections, immune system disorders, or other medical conditions, and to check for changes in an existing blood disorder. It can also be used to monitor the effects of medication or treatment on the body. For example, certain treatments can lower white blood cell counts and weaken the immune system.

A CBC is often part of a routine health check-up, but it can also be used to investigate unexplained symptoms, such as fever, unintended weight loss, night sweats, bruising, bleeding, or fatigue. It can also be used to monitor an ongoing health condition, such as cancer or chronic kidney disease.

The test involves taking a blood sample from a vein in the arm, using a small needle. The procedure usually takes less than five minutes and there is very little risk involved. Results are usually ready within a few days, and can provide important clues about what is happening inside the body, helping to ensure the correct diagnosis and treatment.

Blood lipid test

A blood lipid test is a common blood test that measures the amount of specific fat molecules called lipids in the blood. Lipids include fats and cholesterol, both good and bad, that can build up in body tissues, including the blood. Having too many lipids in your blood can lead to a buildup in your blood vessels and arteries, which can cause damage and increase your risk of cardiovascular problems such as heart disease, heart attack, and stroke.

The lipid panel includes measurements of your cholesterol levels and your triglyceride levels. There are four different cholesterol measurements:

• Total cholesterol: This is your overall cholesterol level — the combination of LDL-C, VLDL-C, and HDL-C.
• Low-density lipoprotein (LDL) cholesterol: This is the "bad cholesterol" that can collect in your blood vessels and increase your risk of cardiovascular disease.
• Very low-density lipoprotein (VLDL) cholesterol: This is usually present in very low amounts in fasting samples, as it mostly comes from recently eaten food. An increase in VLDL in a fasting sample may indicate abnormal lipid metabolism.
• High-density lipoprotein (HDL) cholesterol: This is the "good cholesterol" that helps decrease the buildup of LDL in your blood vessels.

Triglycerides are a type of fat from the food we eat. Excess amounts of triglycerides in your blood are associated with cardiovascular disease and pancreatic inflammation.

A lipid panel can be ordered for several reasons:

• Diagnosis: Testing lipid levels can be part of the diagnosis of other medical conditions, such as liver disease.
• Screening: This is routine testing to determine if your cholesterol is normal or falls into a borderline-, intermediate-, or high-risk category.
• Monitoring: If you have abnormal results on previous tests or other risk factors for heart disease, lipid testing can monitor the cholesterol in your blood.
• Measuring response to treatment: If you have been told to make lifestyle changes or take cholesterol medications, a lipid panel can evaluate your response to treatment.

While a blood lipid test cannot definitively diagnose a stroke, it can help give doctors a picture of what may have caused it. It can also predict major stroke risk and predict the outcome of recovery after a stroke.

Clotting time test

While a stroke cannot be diagnosed with blood work alone, blood tests can be used to determine the cause of stroke symptoms and to rule out other conditions. Blood clotting tests, also known as coagulation tests, are one of the tests that may be performed to help diagnose a stroke. These tests measure how quickly your blood clots and can help determine whether a stroke was caused by a clot (ischemic stroke) or bleeding (hemorrhagic stroke).

In addition to clotting time tests, other blood tests that may be performed to help diagnose a stroke include a complete blood count (CBC) and blood glucose, cholesterol, and thyroid tests. Imaging tests such as CT scans and MRIs are also used to diagnose strokes and determine the type of stroke that occurred.

Imaging tests

• Computed Tomography (CT) Scan: A CT scan is often the first test performed in suspected stroke cases. It uses X-rays to capture detailed images of the brain, revealing bleeding, damage to brain cells, and other issues that could be causing stroke symptoms.
• Magnetic Resonance Imaging (MRI): MRI machines use strong magnets and radio waves to create images of the brain. MRI can detect brain changes caused by a stroke sooner than a CT scan and can also identify bleeding and blood flow problems. It can help rule out other conditions like tumors that may present similar symptoms.
• CT or MR Angiogram: An angiogram is an X-ray movie of the blood vessels that visualizes blood flow. A dye is injected into the veins to create a detailed picture of the blood vessels after a stroke. A CT angiogram is used in conjunction with a CT scanner, while an MR angiogram is used with an MRI machine.
• Carotid Ultrasound: This test employs sound waves to visualize the carotid arteries, which supply blood to the brain. It is often used with a CT or MR angiogram to check for plaque buildup that may be blocking blood flow to the brain.
• Trans-cranial Doppler (TCD) Ultrasound: The TCD ultrasound also uses sound waves to measure blood flow in the brain. It helps identify which artery in the brain is blocked. It is typically used in conjunction with a CT or MR angiogram.
• Electroencephalogram (EEG): This test is less commonly used in stroke diagnosis. It records electrical activity in the brain to determine whether stroke symptoms are actually caused by a seizure, as seizures can sometimes mimic stroke symptoms.

These imaging tests are essential for accurately diagnosing a stroke, pinpointing its location, and determining its type (ischaemic or haemorrhagic). This information guides treatment decisions and helps ensure patients receive the most effective and timely care.

Electrocardiogram (EKG)

An electrocardiogram (ECG or EKG) is a test that checks how your heart is functioning by measuring its electrical activity. An electrical impulse (or wave) travels through your heart with each heartbeat, causing the muscle to squeeze and pump blood from the heart. An EKG can help find heart problems that may have led to a stroke. For example, this test can help diagnose atrial fibrillation or a previous heart attack.

An EKG measures and records the electrical activity that passes through the heart, and a doctor can determine if this electrical activity is normal or irregular. An EKG may be recommended if you are experiencing arrhythmia, chest pain, or palpitations, and an abnormal EKG result can signal a number of different heart conditions.

During an EKG, a number of electrodes—usually a total of 12 to 15—are attached to various locations on your body, including your arm, leg, and chest. The electrodes are attached by small suction cups or adhesive patches, and the sensors in the pads detect the electrical activity of your heart. The test is usually performed while you lie still, and the results are most often recorded on graph paper and interpreted or read by your doctor or a technologist. The test usually takes 5 to 10 minutes.

In the context of stroke diagnosis, an EKG can be used to detect abnormal heart rhythms that may have caused blood clots to form. It can also help detect heart problems, including a recent or ongoing heart attack, abnormal heart rhythms (arrhythmias), coronary artery blockage, areas of damaged heart muscle (from a prior heart attack), enlargement of the heart, and inflammation of the sac surrounding the heart (pericarditis).

Frequently asked questions