Other Laboratory Tests Flashcards
Other laboratory tests that can assist in establishing the cause of anemia include ______________ (to detect hemoglobinuria or an increase in urobilinogen) with a ________________ (to detect hematuria or hemosiderin) and ____________ (to detect occult blood or intestinal parasites).
routine urinalysis, microscopic examination, analysis of stool
Other certain chemistry studies that are useful in establishing the cause of anemia include _________, _______, __________ (to detect excessive hemolysis), and _____________
serum haptoglobin,
lactate dehydrogenase,
unconjugated bilirubin,
renal and hepatic function tests
Iron studies (including serum iron, total iron-binding capacity, transferrin saturation, and serum ferritin) are valuable if ______________ and ______________ are present
an inappropriately low reticulocyte count and a microcytic anemia
___________ and __________ are helpful in investigating a macrocytic anemia with a low reticulocyte count, whereas a ____________ can differentiate autoimmune hemolytic anemias from other hemolytic anemias
Serum vitamin B12 and serum folate assays; direct antiglobulin test
It may be an indication of hereditary spherocytosis
large spleen
A stool positive for occult blood may indicate ______________
iron deficiency
The first step in the laboratory diagnosis of anemia is detecting its presence by the accurate measurement of the _______, __________, ____________, and ___________
hemoglobin concentration, hematocrit, MCV, and RBC count
It is an extremely important tool and is key in the morphologic classification of anemia
MCV
They are characterized by an MCV of less than 80 fL with small RBCs
Microcytic anemias
It is often associated with hypochromia (increased central pallor in RBCs) and an MCHC of
less than 32 g/dL
Microcytosis
Microcytic anemias are caused by conditions that result in reduced________________
hemoglobin synthesis
Heme synthesis is diminished in ___________, ____________ (chronic inflammatory states), and ______________________ (sideroblastic anemia, lead poisoning)
iron deficiency, iron sequestration, and defective protoporphyrin synthesis
It is insufficient or defective in thalassemia and in Hb E disease.
Globin chain synthesis
Iron deficiency is the most common cause of ___________ anemia; the low iron level is insufficient for maintaining normal erythropoiesis.
microcytic
They are characterized by an MCV greater than 100 fL with large RBCs (greater than 8 $m in diameter).
Macrocytic anemias
Macrocytic anemias arise from conditions that result in ______________ development in bone marrow
megaloblastic or nonmegaloblastic red cell
They are caused by conditions that impair synthesis of DNA, such as vitamin B12 and folate deficiency or myelodysplasia.
Megaloblastic anemias
______________ lags behind cytoplasmic development as a result of the impaired DNA synthesis.
Nuclear maturation
__________ anemia is one cause of vitamin B12 deficiency, whereas ________________ is a leading cause of folate deficiency
Pernicious, pregnancy with increased requirements
____________ anemia is characterized by oval macrocytes and hypersegmented neutrophils in the peripheral blood and by megaloblasts or large nucleated erythroid precursors in the bone marrow
Megaloblastic
The MCV in megaloblastic anemia can be markedly increased (up to _________ fL), but modest increases (_________fL ) are most common.
150 fL, 100 to 115 fL
______________ forms of macrocytic anemias are also characterized by large RBCs, but they are typically related to membrane changes caused by disruption of the cholesterol-to-phospholipid ratio.
Nonmegaloblastic
Macrocytic anemias are often seen in patients with ____________, _____________, and ________________
chronic liver disease, alcohol abuse, and bone marrow failure
It is rare for the MCV to be greater than __________ fL in nonmegaloblastic anemias.
115 fL
_____________ anemias are characterized by an MCV in the range of 80 to 100 fL
Normocytic
The RBC morphology on the peripheral blood film must be examined to rule out a dimorphic population of ___________ and _____________ that can yield a normal MCV
microcytes and macrocytes
Some normocytic anemias develop as a result of the premature destruction and shortened survival of _______ (hemolytic anemias), and they are characterized by an elevated ___________ count.
RBCs, reticulocyte
The hemolytic anemias can be further divided into those that result from ________ causes (membrane defects, hemoglobinopathies, and enzyme deficiencies) and those that result from ___________ causes (immune and nonimmune RBC injury).
intrinsic, extrinsic
A ____________ test helps differentiate immune-mediated RBC destruction from other causes of hemolysis.
direct antiglobulin
The ______________ is useful in initially classifying anemias into the categories of decreased or ineffective RBC production (decreased reticulocyte count) and excessive RBC loss (increased reticulocyte count).
absolute reticulocyte count
When the reticulocyte count is
decreased, the MCV can further classify the anemia into three subgroups: ____________, _______________, and ____________.
normocytic anemias, microcytic anemias, macrocytic anemias
The __________ category includes acute
hemorrhage and the hemolytic anemias with shortened RBC survival.
excessive RBC loss
