1. Introduction to hematology

1. Automatic blood analyzer: The type of machine will vary depending on the testing method.

2. Collection of blood samples: mainly use EDTA (ethylenediamine tetra-acetic acid) for anticoagulation.

3. Reasons that may affect the accuracy of hematology tests include lipemia, hemolysis, traumatic collection (such as platelet aggregation), and too urgent a blood draw. When drawing blood, you must pay attention to the design of the anticoagulation tube, draw an appropriate amount of blood, and shake it slowly and evenly so as not to affect the test results. In addition, the thickness of the needle and the speed at which blood is drawn may also affect the test results. Having correct test values ​​is very important for monitoring anemia or disease.

4. A complete hematology test includes CBC (Complete blood counts) and blood smear observation. These tests are accurate tests and can help diagnose blood-related diseases.

Generally speaking, the test items of automatic blood analyzers are mainly hemolysis ratio (hematocrit, Hct), total red blood cell count (RBC), hemoglobin (Hb), total white blood count, WBC), total platelet count (Platelet count), and other values ​​will also be displayed, such as mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin (MCV). Mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW), and some analyzers will also calculate the proportion of reticulocytes. Blood smears can be used to observe the differential WBC count and red blood cell and platelet patterns. Until now, no machine can completely replace the function of blood smears. However, the correct interpretation of blood cytology also requires the accumulation of experience.

2. Anemia

Anemia is the most commonly encountered clinical phenomenon, and it is not a disease. Therefore it is very important to find the cause of anemia. In terms of diagnosis, it can be divided into non-regenerative (Non-regenerative and regenerative anemia. Common causes of non-regenerative anemia include blood loss for less than 3 days, inhibition of erythropoiesis (Erythropoietic suppression), anemia caused by chronic inflammation (Anemia of chronic inflammatory disease, AID), chronic renal failure, metabolic diseases, and drugs. Or factors such as poisoning, infectious diseases (such as parvovirus), bone marrow-related diseases, simple red blood cell aplasia, tumors and radiation therapy.

Common causes of regenerative anemia include highly acute blood loss lasting more than 3 days, some short-term chronic blood loss (but iron deficiency anemia is non-regenerative anemia), and hemolysis. The phenomena that can cause hemolysis include the following causes, such as Pyruvate kinase (PK) deficiency, Phosphofructokinase (PFK) deficiency, immune hemolytic anemia (Immune-mediated hemolytic anemia, IMHA), infection-associated hemolysis, Babesiaspp.), hemolytic anemia induced by chemical drugs or toxins (Chemical/ toxin induced hemolytic anemia, e.g. bee venom), hemolytic anemia induced by blood vessels (Microangiopathic hemolytic anemia), etc. After determining the approximate direction of anemia, further diagnosis can be made. Some serum biochemical tests, re-confirmation of medical history and clinical symptoms, or some special tests such as PCR can be performed to further confirm the cause.

In short, anemia is just a phenomenon, not a cause, so finding out the cause of anemia is very important for treatment. Blood transfusion is definitely not a treatment for anemia, it is just a way to prolong life and buy time to find the cause. Anemia has different causes and different treatments. Incorrect treatment can sometimes make the disease more complicated. Only correct diagnosis can lead to correct treatment.

3. Common causes of anemia in dogs and cats

1. Canine immune hemolytic anemia

Canine immune anemia is caused by the production of antibodies (IgG or IgM, which may cooperate with complement or without complement participation) against red blood cells in the dog's body, causing damage to red blood cells. Anti-erythrocyte antibodies are mainly against normal (called primary IMHA) or altered (called secondary1MHA) antigen on the red blood cell membrane. Any antigen, including infectious pathogens, or that has never been touched or exposed, may bind to the red blood cell membrane and change the antigens on the slug membrane, thus causing the production of anti-erythrocyte antibodies. When the antibody binds to the Ag on the RBC membrane (accompanied by a complement or non-complement reaction), it will lead to: 1. Direct intravascular hemolysis (CIntravascularhemolys is), or agglutination of intravascular RBC; 2. Acceleration of RBC by the spleen or liver It is cleared by the endothelial system (called extravascu la rhemolysis). Immune anemia is usually regenerative anemia (regenerative anemia), but there are also some cases of non-regenerative anemia (nonregenerative anemia). It is generally believed that it is caused by antibodies destroying a certain process in the bone marrow to produce RBCs. Clinical symptoms are usually not obvious in chronic cases. If it is more acute, dark urine or even brown urine may be found, followed by general non-specific symptoms including loss of appetite, not eating, weakness, laziness, exercise intolerance, rapid breathing, vomiting, purging and so on. The physical examination at the time of treatment may show different symptoms depending on the degree of anemia, such as pale mucous membranes, rapid heartbeat, shortness of breath, splenomegaly, hepatomegaly, yellow plague, dark urine, fever, swollen lymph nodes, etc. Common crystal breeds reported abroad include old-fashioned English shepherd dogs, cocker spaniels, poodles, Irish setters, shepherd dogs, Labrador retrievers, etc. In Taiwan, Maltese are the most common breeds. It mostly occurs in middle-aged and older dogs, and there is no difference between males and females.

The main ways to diagnose IMHA include the presence of autoagglutination on blood films (True autoag glut ination), increased spherocytosis (Spherocytosis, anisocytosis, polychrom asia) and positive Coombs' test. If autoagglutination occurs, the disease is more severe and the prognosis may be conservative to poor. Treatment depends on the condition and uses methods such as steroids, immune preparations, intravenous human immunoglobulin, and spleen removal. However, for long-term control, steroids and immunosuppressants are mostly used together.

2. Canine pyrozoonosis

There are two main types of canine pyrozoasis in Asia: Babesi a canis and Babesia gibsoni. Both of them use ticks as the main route of infection. These two types of pyrozoites mostly cause regenerative anemia with large, low-colored balls and thrombocytopenia. Because it is also a hemolytic anemia, clinically, dark to brown urine may be followed by general symptoms including loss of appetite. , not eating, weak, lazy,Symptoms such as exercise intolerance and rapid breathing. In northern Taiwan, the occurrence rate of small scorch bugs is relatively high. Because scorch worms are difficult to remove, the recurrence rate is caused by improper or excessive use of drugs, which leads to many problems. The most commonly recommended treatment strategy today is a combination of AA and CDI. But immunity improvement also plays an important role.

　3. Immune hemolytic anemia associated with leukemia virus in cats

Feline leukemia virus is a retrovirus that mostly infects lymphocytes and mononuclear blood cells. Therefore, different disease forms, such as tumors, may develop depending on the infection route and the amount of virus at the time of infection. (Iymphoma), immune hemolytic anemia, immune insufficiency, etc. In addition to the presence of anemia, IDEXX test kits or PCR or PT-PCR can be used clinically to test whether IMHA is caused by feline leukemia.

4. Chronic kidney disease

The main causes of anemia caused by chronic renal failure are the lack of erythropoietin (EPO) production and the shortened survival period of red blood cells due to azotemia. Therefore, if dogs and cats with chronic renal failure develop orthoglomerative non-regenerative anemia, EPO can be administered to help hematopoietic function. Today, most still use human genetically recombinant EPO. The initial dose is 100IU/KG, Q2D. When the PCV rises to a normal low value, the administration frequency can be extended and administered. Because the EPO administered is a human recombinant gene, some dogs and cats may produce anti-EPO antibodies and become ineffective.

Treatment

For dogs and cats with regenerative anemia, the cause must be removed first, and at the same time, blood transfusion must be performed as soon as possible for severe anemia. For immune hemolytic anemia, if the transfused blood is constantly being destroyed, adrenal glucocorticoids should be used to control it. Supplement hematopoietic substances such as iron preparations, vitamin B12, vitamin B6, and folic acid. For dogs and cats with hemolytic and immune anemia, prednisone acetate tablets 1-2 mg/kg body weight, taken orally. Twice a day, usually for 2-4 weeks. When medical treatment fails, splenectomy may be performed.