Blood tests

This fish is suffering from massive haematemesis which, one the one hand, is very bad news, but on the other hand, makes it very easy to do a blood test.

There are a lot of blood tests. Like, billions. We are going to tell you about the key ones.

Full Blood Count (FBC)

This is common to do. It's pretty much your standard. Especially important to do in infection, heart problems, surgery and anaemia.

• White blood cell (WBC) tells you about of white blood cells per volume of blood. Normal is around 4-11x10⁹/L. Low means immunosuppression, high means infection or cancer.

White blood cell breakdown: looks at the types of white blood cells present.

• • Neutrophils (40-75%) (raised in bacterial infection)
  • Lymphocytes (20-45%) (raised in viral or bacterial infection, and in haematological cancer)
  • Monocytes
  • Eosinophils
  • Basophils

   * Red blood cell (RBC) count: is a count of the actual number of red blood cells per volume of blood. Both increases and decreases can point to abnormal conditions.
   * Haemoglobin measures the amount of oxygen-carrying protein in the blood.
   * Haematocrit measures the amount of space red blood cells take up in the blood. It is reported as a percentage (0 to 100) or a proportion (0 to 1).
   * The platelet count is the number of platelets in a given volume of blood. Both increases and decreases can point to abnormal conditions of excess bleeding or clotting. Mean platelet volume (MPV) is a machine-calculated measurement of the average size of your platelets. New platelets are larger, and an increased MPV occurs when increased numbers of platelets are being produced. MPV gives your doctor information about platelet production in your bone marrow. Mean corpuscular volume (MCV) is a measurement of the average size of your RBCs. The MCV is elevated when your RBCs are larger than normal (macrocytic), for example in anaemia caused by vitamin_b12 deficiency. When the MCV is decreased, your RBCs are smaller than normal (microcytic), such as is seen in  iron deficiency anaemia or thalassaemias.
   * Mean corpuscular haemoglobin (MCH) is a calculation of the amount of oxygen-carrying haemoglobin inside your RBCs. Since macrocytic RBCs are larger than either normal or microcytic RBCs, they would also tend to have higher MCH values. 
   * Mean corpuscular haemoglobin concentration (MCHC) is a calculation of the concentration of haemoglobin inside the RBCs. Decreased MCHC values (hypochromia) are seen in conditions where the haemoglobin is abnormally diluted inside the red cells, such as in iron deficiency anaemia and in thalassaemia. Increased MCHC values (hyperchromia) are seen in conditions where the haemoglobin is abnormally concentrated inside the red cells, such as in hereditary spherocytosis, a relatively rare congenital disorder.
   * Red cell distribution width (RDW) is a calculation of the variation in the size of your RBCs. In some anaemias, such as pernicious anaemia, the amount of variation (anisocytosis) in RBC size (along with variation in shape – poikilocytosis) causes an increase in the RDW.