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53 Cards in this Set
- Front
- Back
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What is plasma?
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The liquid component of whole blood that contains clotting factors
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What are the cellular elements of blood?
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1. Leukocytes: WBCs that have nuclei
2. Platelets: anucleated cellular component of coagulation 3. RBCs (erythrocytes): sacks of hemoglobin which carry oxygen and have no nuclei |
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What is the reference range of a complete blood count (CBC) report?
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The interval where greater than 90% of the values from the normal population would occur
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How is hemoglobin concentration measured?
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By spectrophotometer after red cells are lysed
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How is hematocrit measured?
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After centrifuging a thin tube of blood so that the cellular elements are pushed to one end, the length of the tube occupied by the packed red cells is divided by the total length of the tube occupied by both red cells and supernatant plasma and then multiplied by 100%
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What is the RBC count?
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The number of RBCs per unit of volume measurement of blood. The RBC count can be done two ways. The older, considerably more imprecise method was to dilute a sample of blood and then count the number of RBCs you saw
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What is normal male and female hemoglobin concentration?
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male: 16 +/- 2
female: 14 +/- 2 |
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What is the normal male/female hematocrit?
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male: 47 +/- 5
female: 42 +/- 5 |
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What is the normal male/female RBC count?
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male: 5.4 +/- .7
female: 4.8 +/- .6 |
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What are indices? what are the two classical indices?
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The primary RBC measurements (Hct, Hb, RBC count) can be used to calculate ratios which can be used to determine the nature of blood cell dz
two types: 1. mean corpuscular volume (MCV) 2. mean corpuscular Hgb concentration |
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How do you calculate mean corpuscular volume? what is a normal MCV?
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Hct/RBC x 10; normal = 87 +/- 7 fL
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How do you calculate mean corpuscular Hgb concentration? what is normal?
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Hgb/Hct x 100; normal= 34 +/- 2
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What does the MCV indicate?
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The average size of the RBCs
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What is the most important blood indice?
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mean corpuscular volume
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What is the MCHC?
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A rough guide of what shade of red the RBCs will be. The lesser the MCHC, the paler the cell
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What is erythropoiesis?
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Production of red cells
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What is the function of erythropoietin? what organ secretes it? what is the stimulus for secretion?
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The kidney detects less than normal O2 and secretes erythropoietin into the blood which stimulates the marrow to increase red cell production
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What is the reticulocyte life span?
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2 days in marrow; 1 day in blood = 3 day lifespan
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What is the stimulus of erythropoietin secretion?
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Hypoxia
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What is a normal reticulocyte count?
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.5%-1.5%
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How do you calculate the absolute reticulocyte count?
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RBC count x reticulocyte ratio
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What is the normal reticulocyte count?
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B/e 20 to 100 x 10^3/uL
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If you have a absolute reticulocyte count of 50 x 10^3 w/ 15.0 g/dL hemoglobin what does that indicate about RBC production?
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Normal production
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If you have a absolute reticulocyte count of 200 x 10^3/uL w/ 8.0 g/dL hemoglobin what does that indicate?
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increased erythropoiesis in the presence of anemia (normal retic [ ] = 20 to 100 x 10^3 and normal RBC concentration is 16 in men, 14 in women) so these values indicate failure of red cell survival and attempted compensation by producing more red cells
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What does an absolute retic count of 15 x 10^3/uL w/ 4.0 g/dL hemoglobin suggest?
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Marrow failure to respond to severe anemia; b/c there is decreased reticulocytes in the presence of decreased hemoglobin
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What is anemia?
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Hgb and Hct decreased below normal range
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What is polycythemia?
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too many RBCs - Hgb and Hct above normal range
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What is normocytic?
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normal size (MCV) and shape
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What is macrocytic?
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greater than normal size or MCV
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What is microcytic?
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smaller than normal size or MCV
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What is normochromic?
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normal red color; area of central pallor < 1/2 RBC width
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What is hypochromic?
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paler red color; widened area of central pallor > 1/2 RBC
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What is poikilocytosis?
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variation in RBC shape
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What is anisocytosis?
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variation in size of RBC
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What would you call an anemia w/ RBCs of normal size and shape and color?
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normocytic, normochromic anemia
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If the reticulocyte is low in anemia what does that mean?
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There is a failure of marrow production
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If reticulocyte is increased in anemia what does that mean?
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failure of red cell survival or hemolytic anemia
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If there is a low reticulocyte count and RBCs are normocytic what does that mean?
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1. anemia chronic dz
2. marrow failure |
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Why does anemia chronic dz cause a low reticulocyte count but normocytic RBCs?
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anemia chronic dz (decreased retics or MF) - inflammation blocks iron from getting to erythroid precursors so RBC production is inhibited; most cases are normocytic but severe inflammation can cause micocytosis
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What is aplastic anemia?
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bone marrow that is completely wiped out by a toxin (chemotherapy) or replaced by a tumor
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What dz'es cause RBCs to be microcytic? why?
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1. iron deficiency - not enough iron for hemoglobin to make normal sized RBCs
2. chronic dz - severe inflammation blocks iron from getting to erythroid precursors so RBCS are smaller but more often normocytic |
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What causes megaloblastic anemia? why?
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B12 or folate deficiency - deficiency interferes w/ nuclear replication -> fewer replications -> Macrocytic cells
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What can cause a failure of survival of RBCs (causing increased reticulocyte count)?
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1. bleeding/ hemorrhage
2. hemolytic anemia |
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Why does bleeding cause an increased reticulocyte count and failure of RBC survival?
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in mild forms the blood loss leads to iron deficient anemia
in acute forms massive loss leads to hypovolemic shock but unless the pt is given fluids Hgb will be unchanged for next 4-12 hrs, so reticulocyte will not increase until 3 days later |
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Why does hemolytic anemia cause increased reticulocyte and failure of RBC survival?
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1. immune hemolytic anemia = Ab destroys RBCs
2. non-immune hemolytic anemia = -Red cells normal but damaged by environment: artificial heart valve - Red cells defective or lemons: defective membrane, hemoglobin and/or enzymes |
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What is relative polycythemia? what causes it? what is the serum erythropoietin concentration?
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Red cell mass of body is normal but plasma volume is decreased
-dehydration, diuretics, stress normal EP concentration b/c the O2 delivery is probably normal, just [plasma] decreased |
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What is primary/essential absolute polycythemia? what is it associated with?
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Erythroid malignancy which produces too many RBCs; associated with low serum EP
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What is secondary absolute polycythemia? what is it associated with?
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two categories associated w/ increased EP:
1. secondary to hypoxia: appropriate response in lung dz, cyanotic congenital heart dz 2. secondary to excessive erythropoietin production by tumors: inappropriate response especially in the kidney or liver |
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What is the erythrocyte sedimentation rate (ESR)? what is it used for?
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Measures how far the top of the RBC layer will settle in a tube after 1 hour
Used as a screening test to detect occult inflammation or malignancy |
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How does the plasma protein level affect the ESR?
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the higher the plasma protein concentration the further the RBCs will drop
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What is the most common cause of an elevated ESR?
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increased plasma fibrinogen from inflammation
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What is a myeloma?
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A malignancy of plasma cells
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What effect do elevated plasma proteins have on RBCs?
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increased [ ] of plasma proteins weaken the repelling forces so that weaker attractive forces can bind RBCs together into stacks called rouleaux, RBCs in Rouleaux fall faster
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