Term
| What are some preanalytical sources of error? |
|
Definition
| Poor technique, inappropriate container, interfering substances (hemolysis, lipemia), wrong labeled sample!, damage during transport |
|
|
Term
| What are some analytical sources of error? |
|
Definition
| Expired reagents, change in reagent lot, analyzer limitation, appropriate for species? |
|
|
Term
| What are some sources of post-analytical error? |
|
Definition
| Transcription errors, results for the wrong patient. Oops. |
|
|
Term
| Which blood tubes do not have anticoagulant? |
|
Definition
| Red top tubes, Serum separator tubes (SST, tiger top, marbled) |
|
|
Term
| What do I put in red top tubes? |
|
Definition
| Blood for chemistries, fluids, urine, looking for antibody, hormone or drug levels. |
|
|
Term
| Which tubes have anticoagulants? |
|
Definition
| Purple top (EDTA), green top (heparin), blue top (citrate) |
|
|
Term
| What do I use purple top tubes for? |
|
Definition
| Cell counts in blood or fluid, use plasma for hormones, ammonia. |
|
|
Term
| What do I use green top tubes for? |
|
Definition
| Cell counts (especially with reptiles), use plasma for chemistries, hormones, ammonia |
|
|
Term
| What do I use a blue top tube for? |
|
Definition
|
|
Term
| Ideally how many patients should a reference interval be based on? |
|
Definition
|
|
Term
| What does the sensitivity of a test indicate? |
|
Definition
| The proportion of patients with the disease AND a positive test. |
|
|
Term
| What does the specificity of a test indicate? |
|
Definition
| The proportion of patients without the disease AND with a negative test. |
|
|
Term
| What does efficieny/accuracy indicate? |
|
Definition
| Percentage of patients that are correctly classified by the test |
|
|
Term
| What is the positive predictive value? |
|
Definition
| Probability that a positive test is correct. |
|
|
Term
| Which kind of test is a good screening test? |
|
Definition
| A test with high sensitivity. |
|
|
Term
| What is a test with high specificity good for? |
|
Definition
| It is a good confirmatory test. |
|
|
Term
| How does an impedance counter work? |
|
Definition
| Cells are bad at conducting electricity, so when the cells pass through a current they create resistance proportional to the size of the cell |
|
|
Term
| What are some disadvantages of impedance analyzers? |
|
Definition
| Need daily maintenance, WBC differential count may be less accurate, platelet counts may be inaccurate. |
|
|
Term
| How does flow cytometry work? |
|
Definition
| Cells in suspension flow through a light source, the scatter of light the cell creates is collected and analyzed. |
|
|
Term
| How does flow cytometry work? |
|
Definition
| Cells in suspension flow through a light source, the scatter of light the cell creates is collected and analyzed. |
|
|
Term
| What are some errors introduced with sample age? |
|
Definition
| Platelets decrease and clump, leukocyte morphology changes, RBCs can swell or shrink. |
|
|
Term
| What is the difference between PCV and Hct? |
|
Definition
| PCV is measured manually, while Hct is calculated using the MCV and the RBC count. The numbers should be very close. |
|
|
Term
| What is fibrinogen used to measure? |
|
Definition
| Good indicator of inflammation in ruminants (and horses), increases in fibrinogen are often seen before changes in WBC count. Also increases with pregnancy. |
|
|
Term
| How do you measure fibrinogen from a blood sample? |
|
Definition
| Put your blood in a crit tube, heat it for 3 minutes to make the fibrinogen precipitate, spin it down and measure. |
|
|
Term
| How do you measure fibrinogen from a blood sample? |
|
Definition
| Put your blood in a crit tube, heat it for 3 minutes to make the fibrinogen precipitate, spin it down and measure. |
|
|
Term
| What is the relationship of Hgb to PCV? |
|
Definition
| Hgb should be 1/3 of the PCV!! Know this! |
|
|
Term
| What things artificially increase hgb when measured colorimetrically? |
|
Definition
| Sample turbidity, like lipemia, heinz bodies, cell stroma from high white cell count. Hemolysis will also give you more hgb than you would expect for the RBC count. |
|
|
Term
| What is the MCHC and what affects it? |
|
Definition
| Mean cell hgb concentration. Affected by both RBC count and RBC size. Increased MCHC is an artifact. |
|
|
Term
| What is the approximate RBC lifespan in a dog? In a cat? |
|
Definition
|
|
Term
| What are some clinical signs of anemia? |
|
Definition
| Pale mucus membranes, weakness, lethargy, exercise intolerance, systolic heart murmur, hypotension, weak pulses, maybe pica |
|
|
Term
| What are the compensatory responses to anemia? |
|
Definition
| Tachypnea, tachycardia, ^ cardiac output, ^ 2,3-DPG (releases more O2 into tissue) |
|
|
Term
| What does the MCV indicate? |
|
Definition
| Expression of RBC size. Direct measurement most reliable. Macrocytic- bigger than normal, microcytic- smaller than normal. |
|
|
Term
|
Definition
| The average RBC Hgb concentration (affected by both Hb level and cell volume). Less Hgb than usual- hypochromic. Normochromic within range. Hyperchromasia is an artifact. Can't happen for real. |
|
|
Term
|
Definition
| Average amount of Hgb in average RBC. Same terminology as MCHC. Hyperchromasia still an artifact. |
|
|
Term
| What is the primary finding of a regenerative anemia? |
|
Definition
| Increased immature RBCs in peripheral blood- usually indicated by increased polychromasia or reticulocytosis. |
|
|
Term
| [image] What is the description of the indicated cells? |
|
Definition
| Polychromasia- larger than mature RBCs with dispersed ribosomes and decreased hemoglobin. |
|
|
Term
| What stain do you use to do a reticulocyte count? |
|
Definition
| New Methylene Blue. The stain causes darkening of the ribosomes in the baby RBCs. Reticulocytes are reported as a percentage of the total RBC count. |
|
|
Term
| [image] What is the pattern of this red blood cell? What does it indicate? |
|
Definition
| Basophilic stippling, indicates regenerative anemia. |
|
|
Term
| What are three signs of RBC immaturity? |
|
Definition
| Polychromasia, basophilic stippling, reticulocytes. |
|
|
Term
| What is the hallmark of regeneration in cats and dogs? |
|
Definition
| Polychromasia +/- basophilic stippling. Use retic count to quantify. |
|
|
Term
| What percent of retics is considered regenerative in cats and dogs? |
|
Definition
| Cats: greater than 1%, dogs greater than 1.5% |
|
|
Term
| What is regenerative anemia caused by? |
|
Definition
| Blood loss, hemolysis. There is a greater response with hemolysis, and a greater response with a lower PCV. |
|
|
Term
| What does a large animal regenerative response look like? |
|
Definition
| Basophilic stippling, anisocytosis, +/- polychromasia. |
|
|
Term
| What does an equine regenerative response look like? |
|
Definition
| Horses do NOT release reticulocytes. +/- macrocytosis without polychromasia. |
|
|
Term
| Normocytic, normochromic anemia. |
|
Definition
| Indicates suppressed erythropoeisis, acute or low grade regenerative anemia, equine anemias. |
|
|
Term
| Macrocytic, hypochromic anemia. |
|
Definition
| Strong regenerative response to anemia. |
|
|
Term
| Macrocytic, normochromic anemia. |
|
Definition
| Occasionally seen in regenerative anemia in horses. |
|
|
Term
| Microcytic, hypochromic anemia. |
|
Definition
| Iron deficiency, chronic liver disease. |
|
|
Term
|
Definition
| Unequal sized RBCs, can be large or small. May indicate regenerative anemia, or a maturation defect. Small cells can be fragments or extra divisions of RBCs. |
|
|
Term
|
Definition
| Red cell distribution width- calculates how much the red cell size differs from the mean. |
|
|
Term
| When do we see circulating nucleated RBCs? |
|
Definition
| Lead poisoning, splenic disease, bone marrow damage/disease, hypoxia, seizures, heat stroke, inflammation, Schnauzers |
|
|
Term
| When might we see basophilic stippling? |
|
Definition
| Lead toxicity, bone marrow disorders, drug toxicities (like chloramphenicol), regenerative anemia. |
|
|
Term
| What is poikilocytosis? And what can cause it? |
|
Definition
| Abnormal RBC shapes. Caused by membrane abnormalities, mechanical or chemical injury, oxidative injury, depletion of ATP. |
|
|
Term
| [image] How would you describe these blood cells? |
|
Definition
| Spherocytes, round, dense with no central pallor. Defective bit of membrane has been pinched off by macrophages. Membrane reseals and then the cell gets killed. |
|
|
Term
| What can cause the appearance of spherocytes? |
|
Definition
| RBCs are coated with antibody and get destroyed, or RBC fragmentation. |
|
|
Term
| What are schistocytes and how do they happen? |
|
Definition
| Fragmented pieces of red blood cells, due to microangiopathic hemolysis (RBCs are sheared off while negotiating around inflammatory things). Not usually a direct cause of anemia. |
|
|
Term
| What are Heinz bodies and how do they form? |
|
Definition
| Amorphous precipitates of oxidized, denatured hemoglobin. They stain as a pale round bubble usually on the edge of the cell. |
|
|
Term
| [image]What are the structures at the edge of the cells called? |
|
Definition
| Heinz bodies, caused by oxidative stress. |
|
|
Term
|
Definition
| When the hemoglobin gets pushed to one side of the RBC due to oxidative damage. |
|
|
Term
|
Definition
| Crenated cells with uniform blunt or sharp projections. |
|
|
Term
| What are some causes of echinocytes? |
|
Definition
| Uremia, changes in membrane phospholipids, RBC dehydration, RBC ATP depletion, an artifact of various things. |
|
|
Term
|
Definition
| Bizzare, ameboid looking RBCs with asymmetrical spicules that vary in length and thickness. |
|
|
Term
| What causes acanthocytes? |
|
Definition
| Excess cholesterol in the membrane (for various reasons), lipophilic drugs. |
|
|
Term
| What causes acanthocytes? |
|
Definition
| Excess cholesterol in the membrane (for various reasons), lipophilic drugs. |
|
|
Term
|
Definition
| Abnormally thin RBCs, may appear thin and pale. |
|
|
Term
| What are codocytes (or 'target' cells)? |
|
Definition
| A red blood cell that looks like a bullseye, Hgb is concentrated in the center of the cell. Causes are immature RBCs, increased cholesterol, splenectomy, iron deficiency. |
|
|
Term
| What are causes of regenerative anemia? |
|
Definition
| Blood loss: acute, chronic, internal, external. Can lead to iron deficiency. Hemolysis: intravascular, extravascular. |
|
|
Term
| What is the hallmark of blood loss? |
|
Definition
| Combined decrease in both PCV and total protein. |
|
|
Term
| What is a normal reticulocyte percentage in a dog? Cat? |
|
Definition
| Dog: 0-2%, up to .5% aggregate, up to 10% punctate |
|
|
Term
| What absolute reticulocyte count in a dog is considered regenerative? In a cat? |
|
Definition
| Dog: >60,000. Cat: >50,000 |
|
|
Term
| What reticulocyte percentage is regenerative in a cat? Dog? |
|
Definition
| >1% in cats, >1.5% in dogs. |
|
|
Term
| How many days does it take to see reticulocytosis following blood loss? |
|
Definition
| 3-5 days. Normal PCV in 1-4 weeks. |
|
|
Term
| What blood parameter normalizes first after blood loss? |
|
Definition
| Total protein normalizes first. Albumin shifts back into vasculature. More albumin production. Recovery from internal blood loss is faster. |
|
|
Term
| What are two body iron stores? |
|
Definition
| Ferritin and hemosiderin. |
|
|
Term
| How is iron transported in blood? |
|
Definition
|
|
Term
|
Definition
| A transported that moves iron from GI cells into the blood. |
|
|
Term
| How is iron absorption regulated? |
|
Definition
| By an unknown signal from the bone marrow. This signal regulates ferroportin levels. One oral dose of iron decreases the absorption of a second dose becaues the first dose increases hepcidin. Hepcidin breaks down ferroportin molecules. |
|
|
Term
| How can transferrin be related to iron deficiency? |
|
Definition
| With iron deficiency, the liver increases production of transferrin. In anemia, transferrin may have decreased saturation. |
|
|
Term
| Inflammation will decrease liver production of transferrin. |
|
Definition
| Can contribute to the anemia of chronic disease. Lots of inflammation, less transferring, less iron around, anemia! |
|
|
Term
|
Definition
| Thousands of iron atoms embedded in a protein shell that prevents the formation of reactive oxygen species. Iron is dangerous when it goes rouge! |
|
|
Term
| What are the functions of hepcidin? |
|
Definition
| Hepcidin is the master iron regulator! It stimulates the degradation of ferroportin, which inhibits intestinal absorption, and it inhibits the release of iron from macrophage stores. |
|
|
Term
| What is iron deficiency usually caused by? |
|
Definition
| External blood loss, like bleeding GI tumor, parasites. Can sometimes be from dietary malabsorption. |
|
|
Term
| What abnormalities do you see with extravascular hemolysis? |
|
Definition
| Bilirubinemia, bilirubinuria, RBC morphologic abnormalities. |
|
|
Term
| What abnormalities do you see with intravascular hemolysis? |
|
Definition
| Billirubinemia, bilirubinuria, hemoglobinemia, hemoglobinuria, RBC morphologic abnormalities. |
|
|
Term
| T/F: Immune mediated hemolysis is usually extravascular. |
|
Definition
| True. It can be intravascular with complement fixation. |
|
|
Term
| What does a positive Coombs test indicate? |
|
Definition
| There is antibody against a 'material' adherent to the RBC. |
|
|
Term
| T/F: Sphereocytes are not usually caused by an immune mediated process. |
|
Definition
| F. They usually are. Spherocytes are caused by partial phagocytosis of RBC membrane by splenic macrophages. Usually triggered by a membrane defect. |
|
|
Term
| T/F: It is easy to identify spherocytes in species with small RBCs. |
|
Definition
| False. It is hard to identify spherocytes in species with small RBCs (like cat, horse, ruminants). Their RBCs can look like spherocytes. |
|
|
Term
| How do you determine whether autoagglutination is actually rouleaux? |
|
Definition
| Dilute the blood with saline. Rouleaux would disperse with dilution. |
|
|
Term
| What is icterus a sign of? |
|
Definition
| Hyperbilirubinemia. Possible ddx are liver disease, biliary obstruction, or hemolysis. |
|
|
Term
| What are some characteristics of IMHA? |
|
Definition
| Associated with strong regenerative response (takes 3-5 days), can also cause an inflammatory leukogram, strongly suggested by spherocytosis, confirmed by autoagglutination. May need a Coombs test. When autoagglutination is present you do NOT need a Coombs test. |
|
|
Term
| Why are cat blood types weird? |
|
Definition
| Type A cats have naturally occuring antibodies to B, and vice versa. Type AB cats don't have antibody against either. Therefore if you give type A blood to a type B cat, it triggers severe intravascualr hemolysis and possibly death. |
|
|
Term
| Why can we safely transfuse a horse or a dog ONCE without a problem? |
|
Definition
| Dogs and horses lack naturally occuring antibodies. The first transfusion with incompatible blood with sensitize the animal to a reaction on a second transfusion. |
|
|
Term
| What do chocolate-brown mucous membranes indicate? |
|
Definition
| They are evidence of methemoglobinemia. Methemoglobin forms within minutes of exposure to antioxidants. |
|
|
Term
| What findings are indicative of nonregenerative anemia? |
|
Definition
| Absence of polychromasia or insufficient reticulocytosis. |
|
|
Term
| What are the main causes of nonregenerative anemia? |
|
Definition
| Acute blood loss or hemolysis, anemia of inflammation/chronic disease, iron depletion, renal disease, chronic liver disease, hypothyroidism, hypoadrenocorticism, bone marrow disease. |
|
|
Term
| What is anemia of inflammation commonly associated with? |
|
Definition
| Inflammatory processes, chronic infections, tissue injury, fractures, neoplasia. Most common cause of anemia in small animals!! |
|
|
Term
| What are the qualities of anemia of inflammation? |
|
Definition
| MILD nonregenerative anemia, that is normocytic, normochromic. Also called anemia of chronic disease. |
|
|
Term
| Mechanism of anemia of renal disease |
|
Definition
| Moderate to severe nonregenerative anemia- caused by decreased production of Epo and decreased RBC survival. |
|
|
Term
| What is the mechanism of anemia of liver disease? |
|
Definition
| Impaired mobilization of iron stores (because liver isnt making transferrin), impaired marrow response, decreased RBC survival. Usually normocytic, normochromic. |
|
|
Term
| What is pure red cell aplasia? |
|
Definition
| Selective reduction of erythroid precursors in the marrow. Cats: usually from FeLV, dogs: usually immune mediated |
|
|
Term
|
Definition
| Decreased production of ALL cell lines in the marrow. The marrow is filled with adipose cells. Lymphocytes are not as affected. |
|
|
Term
| What on signs of aplastic anemia? |
|
Definition
| Pancytopenia on CBC- nonregenerative anemia, thrombocytopenia, neutropenia. Can lead to unexplained infections and unexplained bleeding. |
|
|
Term
| What are some causes of aplastic anemia? |
|
Definition
| Drugs, infectious agents, toxins, radiation/chemo, idiopathic. |
|
|
Term
| What is the most antigenic blood group in the dog? |
|
Definition
|
|
Term
| Which equine blood types are the most antigenic? |
|
Definition
|
|
Term
| Which organisms cause feline infectious anemia? |
|
Definition
| Mycoplasma haemofelis and Mycoplasma haemominutum. |
|
|
Term
| Where are platelets produced? |
|
Definition
| In the bone marrow from megakaryocytes. |
|
|
Term
| What is the basic platelet structure? |
|
Definition
| They are discoid, anucleate cytoplasmic fragments 5-7 um in length. |
|
|
Term
| What does thrombopoietin do? |
|
Definition
| It is released by various locations in the body, and in circulation binds to platelets, and once its bound becomes inactive. If few circulating platelets are around, there will be more unbound thrombopoietin which will stiumlate megakaryocyte production and platelet release. |
|
|
Term
| Which part of the platelet is the first to sense change in the vasculature? |
|
Definition
| The glycocalyx, which is covered with receptors that facilitate platelet adhesion. |
|
|
Term
| What does the platelet open canalicular system do? |
|
Definition
| It allows the movement of substances between platelets and plasma so platelets dont need to lyse. It also helps increase surface area of the platelet which is important when activated. |
|
|
Term
| Why is the dense tubular system of the ER so important in the platelet? |
|
Definition
| It stores calcium which is essential for platelet activation and synthesizes thromboxane. |
|
|
Term
| Which platelet organelles are visible by light microscopy? |
|
Definition
| Alpha granules, they are the dark blue granules. They have important things in them! |
|
|
Term
| What are the functions of platelets? |
|
Definition
| Primary hemostasis (formation of the inital plug), secondary hemostasis, recruit inflammatory cells, repair wounds. |
|
|
Term
| How do we assess platelets in the patient? |
|
Definition
| Quantitative: platelet count, mean platelet volume, blood smear estimate, plateletcrit. Qualitative: buccal mucosal bleeding time, thromboelastography. |
|
|
Term
| How many platelets should you typically count per 100x field (in a dog and cat)? |
|
Definition
| 10 per 100x field. If you count less and don't see clumps, you should suspect thrombocytopenia. |
|
|
Term
| What are some signs of thrombocytopenia? |
|
Definition
| Mucosal bleeding, petechiae, ecchymoses, epistaxis, hematuria, post op bleeding. |
|
|
Term
| Which WBCs are granulocytes? |
|
Definition
| Neutrophils, eosinophils, basophils. |
|
|
Term
| What are the main functions of neutrophils? |
|
Definition
| Phagocytosis and antimicrobial activity. |
|
|
Term
| What percentage of the neutrophil count must bands be to be considered a significant left shift? |
|
Definition
| Greater than 10% of the neutrophil count. |
|
|
Term
| What is a degenerative left shift? |
|
Definition
| A degenerative left shift means that immature cells outnumber segs. Usually a poor prognosis. |
|
|
Term
| What is the most common cause of toxic change in neutrophils? |
|
Definition
| Endotoxemia due to bacterial infection. Cells are insulted during their maturation in the bone marrow. |
|
|
Term
| What are some morphological changes that come along with toxic change in neutrophils? |
|
Definition
| Increased cytoplasmic basophilia, Dohle bodies, foamy vacuolated cytoplasm, toxic granulation, nuclear swelling. |
|
|
Term
| What are the two basic mechanisms for neutrophilia? |
|
Definition
| Increased prodcution (inflammation, myeloproliferative disorders), shift of neutrophils from marginal circulating pool (corticosteroid, epinephrine) |
|
|
Term
| What qualifies a mature neutrophilia? |
|
Definition
| A neutrophilia with NO left shift. Consists of only mature neutrophils. |
|
|
Term
| When might we see a corticosteroid-induced leukocytosis? |
|
Definition
| Pain, chronic stress, corticosteroid therapy, hyperadrenocorticism. Common in dogs, not so much in cats. |
|
|
Term
| What is the typical pattern of a corticosteroid leukocytosis? |
|
Definition
| Neutrophilia (without a left shift, or very mild) because neutrophils are shifted from the marginal to the circulating pool and some are released from the storage pool. Monocytosis, and lymphopenia. |
|
|
Term
| What is the most characteristic feature of the corticosteroid/stress leukogram? |
|
Definition
| Lymphopenia. Should be low or at least low normal, and may not show the other characteristics. |
|
|
Term
| What is the typical pattern of an epinephrine/physiologic leukocytosis? |
|
Definition
| Neutrophilia with NO left shift (up to 2x normal, demarginates all the neutrophils), lymphoCYTOSIS (opposite of corticosteroid leukogram), very short lived leukocytosis. |
|
|
Term
| What is the typical pattern of an epinephrine/physiologic leukocytosis? |
|
Definition
| Neutrophilia with NO left shift (up to 2x normal, demarginates all the neutrophils), lymphoCYTOSIS (opposite of corticosteroid leukogram), very short lived leukocytosis. |
|
|
Term
| What consists of a inflammatory leukogram? |
|
Definition
| A neutrophilia, very often with a left shift. Monocytosis sometimes happens. Lymphopenia often occurs, usually in actue inflammation. |
|
|
Term
| What are some causes of neutropenia? |
|
Definition
| Decreased production, increased tissue demand, shift of cells from circulating to marginal pool. |
|
|
Term
| What are some common causes of lymphocytosis? |
|
Definition
| Epinephrine, chronic antigen stimulation, hypoadrenocorticism, lymphoid neoplasia. |
|
|
Term
| What are common causes of lymphopenia? |
|
Definition
| Increased corticosteroid levels, acute infections, loss of lymph into various places, hereditary immunodeficiency. |
|
|
Term
| When would I usually see basophilia/ |
|
Definition
| Parasitic disease, allergic disease, rarely neoplasia. |
|
|
Term
| Where is active bone marrow retained in the adult? |
|
Definition
| In the epiphyses and in flat bones (sternum, pelvis, ribs, vertebrae) |
|
|
Term
| Where does EPO come from and what is its release stimulated by? |
|
Definition
| Released by peritubular interstitial cells of the kidney, and it stimulated by hypoxia. |
|
|
