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57 Cards in this Set
- Front
- Back
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What are some complications of venipuncture?
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1. hemoconcentration and falsely elevated values due to prolonged tourniquet application
2. hematoma 3. fainting of patient a. vasovagal response b. treat by elevating legs and placing patient in supine position |
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Describe venipuncture in infants.
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1. special problems due to:
a. small veins b. difficulty in restraining 2. careful restraint and inspection of veins 3. warm heals for heal sticks |
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What are some examples of anticoagulants?
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1. trisodium citrate
2. Ethylenediaminetetraacetic acid (EDTA) 3. Heparin |
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Describe trisodium citrate as a anticoagulant.
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1. removes calcium
2. used for studies of blood coagulation and platelet function |
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Describe EDTA as an anticoagulant.
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a. most commonly used anticoagulant
b. chelates calcium c. preferred for blood counts, cell morphology if fresh blood not available and platelet counts. |
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Describe Heparin as an anticoagulant.
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a. inactivates thrombin; factors IXa, Xa and XIIa
b. anticoagulant of choice for osmotic fragility test c. not satisfactory for: 1) blood films - distorts WBCs and platelets 2) coagulation studies |
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What are some sources of error in blood collection and study?
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1. blood cells begin swelling within six hours at room temperature, therefore ESR should be performed within two hours.
2. inaccurate results will occur with inadequate mixing a. minimum of 60 inversions b. two minutes on a mechanical mixer 3. make slide films immediately from fresh blood |
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What are the components of the CBC?
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1. RBC count
2. WBC count 3. Hematocrit 4. Hemoglobin (Hgb) 5. Red Blood Cell Indices 6. Red Cell Distribution Width (RDW) 7. Platelet counts 8. Differential 9. Additional tests |
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Describe the RBC count.
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1. least precise of all manual hematologic tests
2. automated instruments are more accurate 3. various preanalytical variables also impact inaccuracy of count a. rouleaux 1) stack of coin appearance 2) increased -globulins, fibrinogen, and other plasma proteins, e.g., multiple myeloma b. large clumps (random arrangement) 1) usually IgM 2) agglutination at room temperature, e.g., cold agglutinins |
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What is the normal range for the WBC count?
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5,000 - 10,000 / mm^3 = 5,000 - 10,000 / microL
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Descreibe the use of electronic counting to count WBC.
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1) RBCs lysed prior to counting WBCs using impedance or light scattering
2) nucleated RBCs are counted |
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When does one have to correct for nucleatede RBCs?
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must correct for nRBC when more than 10 nRBC/100 WBC counted
can correct for it by the following equation: true WBC count = (total WBC count * 100) / (100 + nRBC) |
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Describe hematocrit.
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1. ratio of volume of RBC to whole blood expressed as percent
2. does not reflect RBC mass a. dependent on relative plasma volume b. changes in plasma volume will affect hematocrit |
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How is Hemoglobin measured?
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a. spectrophotometrically
b. cyanmethemoglobin method hemoglobin -> methemoglobin -> cyanmethemoglobin |
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What can cause in INC in hemoglobin concentrations?
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1) secondary polycythemia
a) smoking b) people living at high altitudes 2) undue stress or pain a) INC catecholamines -> vasoconstrict blood vessels b) reduce plasma volumes -> hemoconcentration c) may increase Hgb up to 1 g/dL |
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What can cause a DEC in Hb concentrations?
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1) pregnancy
a) disproportionate increase in plasma volume over increase in RBC mass b) reduction of Hgb by approximately 1 g/dL in second and third trimesters c) also see decrease in Hct & RBC count 2) bed rest - often see drop in values of 1 g/dL in 24 hrs 3) children a) lower Hgb than adults b) related to increase in 2,3 DPG (disphosphoglycerate) as result of increased serum phosphate from bone growth c) shift of oxygen dissociation curve to right - O2 readily delivered to tissues - decreased need for erythropoietin - Hgb, Hct and RBC count are less than adult - by puberty, serum phosphate at level of adult |
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WHat is the normal reference range for Hb in newborns, infants, child, adult male, adult female, pregnant female?
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newborn-15-23
infant- 10-14 child- 12-16 adult male- 14-18 adult female- 12-16 pregnant female- 11-15 |
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Explaine the significant drop in Hb after birth.
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1) decrease in erythropoiesis during infancy while Hgb F switches to Hgb A production
2) iron stores increase during this period of RBC breakdown a) iron deficiency is, therefore, rare in early infancy b) may see this between 9 months and 2 years if dietary supplement to milk is not provided |
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Explain the change in Hb in pregnant female.
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plasma volume increases more than RBC mass
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What is Mean Corpuscular Volume (MCV)
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represents the volume of an average RBC expressed as:
MCV (fL) = (Hct * 10) / (RBC (in millions/microL)) |
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What are the values for MCV?
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normal = 80-100 fl
microcytic = < 80 fl macrocytic = > 100 fl |
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What is Mean Cell Hemoglobine (MCH) and how is it calculated?
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content (weight) of Hb in the average RBC, expressed as:
MCH (pg) = (Hb * 10) / (RBC (in millions/microL)) |
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What is the normal value for MCH?
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b. normal = 27-33 pg
c. has very little clinical use |
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What is mean corpuscular hemoglobin concentration (MCHC) and how is it calculated?
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average hgb concentration in a given volume of packed RBCs expressed as:
MCHC (g/dL) = (Hb * 100) / (Hct) |
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What is the normal value for MCHC?
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normal = 32-36 g/dL
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What is Red Cell Distribution Width (RDW) and what is its normal value?
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1. provides measure of size variation of RBCs (anisocytosis)
2. normal = 12.0-16.2% |
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What disease is assocaited with normal RDW levels but low, high and normal MCV?
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3. normal RDW
a. low MCV = thalassemia b. high MCV = hypoplastic anemias c. normal MCV = anemia of chronic disease or hypoplastic anemias |
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What disease is assocaited with high RDW levels but low, high and normal MCV?
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4. high RDW
a. low MCV = iron deficiency, microangiopathic hemolytic anemia, hemoglobin S/thalassemia, or Hgb H disease b. high MCV = megaloblastic anemia or cold agglutinins c. normal MCV = extramedullary hematopoiesis or sideroblastic anemia |
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What is the normal referrence range for platelet count?
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normal = 150,000-450,000/microL
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What is thrombocytopenia?
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3. thrombocytopenia – low platelets
a. finger sticks, heel sticks and platelet satellitism b. diseases: thrombotic thrombocytopenia purpura (TTP), immune thrombocytopenia purpura (ITP), disseminated intravascular coagulation (DIC) hemolytic uremic syndrome (HUS), leukemias with exception of chronic myelogenous leukemia (CML) |
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What is thrombocytosis?
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4. thrombocytosis – elevated platelets
a. malignancies: polypcythemia rubra vera, essential thrombosthemia, CML b. iron deficiency anemia c. reactive thrombocytosis |
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What are the normal differential levels?
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neutrophils-50-70%
bands (stabs)-2-6 lymphocytes-20-40 monocytes-2-8 eosinophils-1-3 basophils -0-1 |
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Physiologically, what can cause neutrophilia?
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a) exercise
b) stress c) emotion d) dramatic temperature changes, etc. |
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Pathologically, what can cause neutrophilia?
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a) bacterial infections - exceptions include:
- neutrophils are low or normal often with lymphocytosis in typhoid fever, tuberculosis, listeriosis, brucellosis, etc. - some severe or overwhelming infections, e.g., gram negative septicemia b) noninfective tissue damage - coronary thrombosis - crush injuries - pulmonary embolism or infarction - poisoning - burns - acute blood loss - rapidly growing tumors, etc. c) metabolic disorders - diabetic ketoacidosis - uremia, etc. d) acute inflammatory response |
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What can cause neutropenia?
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1) aplastic anemia
2) pancytopenia 3) bone marrow damage a) x-irradiation b) drugs (toxic or chemotherapeutic) c) poisons 4) some severe or overwhelming infections, e.g., some cases of gram negative sepsis 5) pernicious anemia 6) some chronic alcoholics 7) familial |
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What is a normal value for leukocyte alkaline phosphatase (LAP)?
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normal score: 30-100
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In what situations is there a DEC LAP?
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decreased in chronic myelogenous leukemia (AML) and paroxysmal nocturnal hemoglobinuria (PNH)
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In what situations is there an INC LAP?
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-increased in leukemoid reactions
-increased in various myeloproliferative disorders such as polycythemia rubra vera and many non-neoplastic disorders causing neutrophilia |
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What can cause eosinophilia?
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1) allergic conditions
2) parasitic infections a) response to parasite antigens b) allergic reaction to foreign material 3) some skin diseases, e.g., eczema 4) some malignancies, e.g., approximately 10% of Hodgkin’s patients |
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What can cause eosinopenia?
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1) steroid therapy
2) after stress - severe infections - trauma - burns - surgery - strenuous exercise, etc. |
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Describe basophils.
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a. rarely seen
b. basophilia – consider underlying malignancy, i.e. chronic myelogenous leukemia (CMC) |
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Describe monocytes.
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a. mature in tissue as macrophages (histiocytes)
b. monocytosis 1) certain types of infections-tuberculosis, typhoidand protozoal, e.g., malaria 2) collagen diseases 3) ulcerative colitis, etc. c. chronic inflammatory conditions |
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When is lymphocytosis seen?
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1) viral infections, i.e., infectious mononucleosis
2) tuberculosis 3) listeriosis 4) some malignancies, etc. |
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When is lymphopenia seen?
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1) chemotherapeutic agents
2) certain immunodeficiency diseases 3) uremia 4) stress, e.g., trauma, burns, etc. |
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Describe neonatal leukocytosis.
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a. WBC is normally 18,000-22,000 at birth (may be even higher in premature infants)
b. drops to 8,000-16,000 after 3-4 days c. adult levels reached around age of 6 months d. postnatal period - neutrophilia is common |
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What is the normal value for reticulocytes in adults and infants?
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1. adult = 0.5-1.5%
2. infants = 2.5-6.5%; falls to adult levels within two weeks of delivery |
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What are retics?
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b. immediate precursor to mature RBC
1. contain RNA and continues to synthesize hemoglobin after loss of nucleus 2. vital stain necessary 3. provides estimate of rate of RBC production |
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How is retic calculated?
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% retics = (retic count/1000RBCs) / (10)
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Describe corrected retic count.
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1. retic count (%) not true reflection of retic production in states of anemia
2. (retic % X patient Hct) / (normal Hct (45)) = corrected retic count |
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What is reticulocyte production index (RPI)?
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1. corrected retic count may be falsely high when there is premature release of retics from marrow
2. premature retics = stress or shift retics a) require 2 - 2 1/2 days to lose reticulum vs. normal retics, which require 1 day b) peripheral smears indicate presence of many polychromatophilic, macrocytic RBCs c) if using retics to evaluate erythropoiesis, must correct for both RBC count and presence of shift retics |
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How is RPI calculated?
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((retic count (%) X patient Hct) / (normal Hct (45)) / (stress (shift) retic maturation time)
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What happens with a RPI > 3.0?
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RPI > 3.0 is most likely due to hemolytic anemia
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What is Erythrocyte Sedimentation rate (ESR)?
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measurement (mm) of the length of fall of erythrocytes in a standardized tube in a given amount of time
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Describe the Westergren method to measure ESR.
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1. 30 cm column with internal diameter of 2.5 mm
2. calibrated from 0-200 mm 3. tube filled with blood and placed vertically 4. distance of fall is read in mm 5. normal: ≤ 15 mm/60 min (males) ≤ 20 mm/60 min (females) |
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What role does rouleaux formation have on ESR values?
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rouleaux formation favors elevated ESR values:
1. increased levels of fibrinogen and acute phase proteins 2. decrease zeta potential and favors rouleaux formation |
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What else influences ESR?
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1. anemia
2. hemolysis 3. temperature 4. anisocytosis, etc |
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Where is ESR elevated in?
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1. inflammation
2. infections 3. monoclonal gammopathies 4. malignancies 5. RA 6. pregnancy, etc. |
