Blood Tests Flashcards
What is a full blood count (FBC)?
A Full Blood Count (FBC) is a test that measures various components of the blood to assess overall health and detect many conditions, like infections, anemia, and bleeding disorders.
Red Blood Cells (RBC)
What it measures: The number of red blood cells in the blood.
If low (Anemia): Causes fatigue, weakness, and pale skin. Can be due to nutritional deficiencies,
iron deficiency or blood loss (e.g., from surgery or injury).
If high (Polycythemia): Can cause the blood to become too thick, increasing the risk of clots. This could happen with conditions like dehydration or lung conditions.
Haemoglobin (Hb)
What it measures: The amount of hemoglobin in the blood, which carries oxygen to tissues.
If low: Indicates anemia, leading to fatigue, dizziness and poor growth. This can be due to iron deficiency, blood loss, or chronic disease. there isn’t enough oxygen getting to the tissues.
If high: May suggest dehydration, chronic lung disease, or a bone marrow disorder that makes the body produce too many red blood cells.
Hematocrit (HCT)
What it measures: The percentage of blood volume that is made up of red blood cells.
If low: Indicates anemia (same as low hemoglobin), causing weakness and fatigue.
If high: Could indicate dehydration or polycythemia, or disorders that increase red blood cell production, such as certain heart or lung diseases.
White Blood Cells (WBC)
What it measures: The number of white blood cells in the blood, which help fight infection.
If low (Leukopenia): Increases the risk of infection, which could happen in conditions like viral infections, bone marrow issues, medication effects or after chemotherapy.
If high (Leukocytosis): Can signal infection (especially bacterial), inflammation, or conditions like leukaemia.
Platelets (PLT)
What it measures: The number of platelets, which help stop bleeding by forming clots.
If low (Thrombocytopenia): Increases bleeding risk, causing easy bruising, frequent nosebleeds, or internal bleeding. Causes include viral infections, certain medications, or bone marrow disorders.
If high (Thrombocytosis): Can lead to excessive clotting, which can cause blood clots in the veins or arteries, leading to a risk of stroke or heart attack.
Mean Corpuscular Volume (MCV)
What it measures: The average size of red blood cells.
If low (Microcytic): Often seen in iron deficiency anemia (small red blood cells).
If high (Macrocytic): Could suggest a vitamin B12 or folate deficiency.
Mean Corpuscular Hemoglobin (MCH)
What it measures: The average amount of hemoglobin in each red blood cell.
If low: Suggests iron deficiency anemia.
If high: Might indicate vitamin B12 or folate deficiency.
Mean Corpuscular Hemoglobin Concentration (MCHC)
What it measures: The concentration of hemoglobin in red blood cells.
If low: Indicates anaemia, especially in conditions like iron deficiency or thalassemia.
If high: Rare
Sodium (Na+)
What it measures: The concentration of sodium, an electrolyte that helps regulate water balance and nerve function.
If low (Hyponatremia): Can cause symptoms like confusion, seizures, and lethargy. It can result from dehydration, kidney problems, or excessive fluid intake.
If high (Hypernatremia): Can cause dehydration, confusion, and damage to organs, often due to excessive loss of water or not enough water intake or diabetes insipidus.
Potassium (K+)
What it measures: The level of potassium, an electrolyte critical for heart function and muscle contraction.
If low (Hypokalemia): Can lead to muscle weakness, irregular heart rhythms (arrhythmias), and fatigue. Causes include vomiting, diarrhea, or certain medications (e.g., diuretics).
If high (Hyperkalemia): Can be life-threatening and cause heart arrhythmias or even cardiac arrest. It’s often seen in kidney failure or certain medications like ACE inhibitors.
Chloride (Cl-)
What it measures: The level of chloride, an important electrolyte that helps maintain fluid balance and pH levels (acid-base balance).
If low (Hypochloremia): Can cause muscle spasms/cramps, irregular/breathing issues, and dehydration and and metabolic alkalosis (excessive base in the blood).
If high (Hyperchloremia): Often seen with dehydration, kidney disease, or metabolic acidosis, a condition where the blood becomes too acidic.
Bicarbonate (HCO3-)
What it measures: The level of bicarbonate, which helps regulate pH balance in the blood.
If low (Metabolic Acidosis): Can cause deep breathing, fatigue, and confusion. May be seen in conditions like kidney disease, uncontrolled diabetes, or severe dehydration.
If high (Metabolic Alkalosis): Can cause nausea, muscle twitching, irritability and confusion, typically due to vomiting or excessive use of antacids.
Urea
What it measures: A waste product from the breakdown of protein.
If high (Uremia): Indicates kidney problems, dehydration, or a high-protein diet. Symptoms include fatigue, nausea, and confusion.
If low: Can be seen in liver disease or malnutrition.
Creatinine
What it measures: A waste product from muscle metabolism, primarily eliminated by the kidneys.
If high: Indicates kidney dysfunction or dehydration. It can signal the need for further kidney tests.
