EXAM #1: CLINICAL INTERPRETATION OF LAB EXAMS Flashcards
What is the definition of normocytic?
Normal MCV/ size
What is the definition of normochromic?
Normal concentration of Hb
What is the definition of anisocytosis?
Blood cells are of UNEQUAL size
What is the definition of poikilocytosis?
Abnormally shaped RBCs
What is the normal MCV of a RBC?
80-100 FL
What is the definition of macrocytic?
MCV greater than 100 FL
What is the definition of microcytic?
MCV than 80 FL
How are anemias classified?
1) Etiology
2) Mean Corpuscular Volume (MCV)
What are the three classifications of anemia based on MCV?
1) Microcytic
2) Macrocytic
3) Normocytic
What are the three classifications of anemia based on etiology?
1) Impaired RBC production
2) Increased RBC destruction
3) Blood loss*****
What is the first lab test to order in a patient with suspected anemia?
CBC, Complete Blood Count
What are the elements of a CBC?
1) Hb= Hemoglobin
2) Hct= Hematocrit
3) PCV= Packed Cell Volume
4) RBC count
5) RBC indices
6) RDW= Red Cell Distribution Width
7) WBC count
- TLC= Total Leukocyte Count
- Diff= differential leukocyte count
8) Platelet count
9) PBS= Peripheral Blood Smear
What are the three RBC indices?
1) MCV= Mean Corpuscular Volume*****
2) MCH= Mean Corpusular Hemoglobin
3) MCHC= Mean Corupusuclar Hemoglobin COncentration
This is the most important value in differentiating anemias
What additional lab values would help to differentiate anemias secondary to a CBC?
1) Reticulocyte count
2) ESR= erythrocyte sedimentation rate
3) Bone marrow exam
What is the normal leukocyte differentiation?
Neutrophil= 50% - 74% Lymphocyte= 26% - 46% Monocyte= 2 - 12% Eosinophil= 0.0 - 5.0% Basophil= 0.0 - 2.0%
What is a reticulocyte count?
- Reticulocytes are precursors to RBCs –this is a count of reticulocytes
- Used to determine the efficacy of erythropoiesis
What is the utility of the ESR?
Elevation indicates an underlying inflammation/ organic disease
What does an elevated reticulocyte count indicate? What is a normal retic count?
Anemia
Note that normal is 0.5-1.5%*
What do you need to remember about retic. counts in anemia?
These values need to be CORRECTED for the degree of anemia.
How is a retic. count corrected?
(patient Hct/45) x retic count
How are reticulocytes identified?
- Retics have RNA while mature RBCs do NOT
- Stain with RNA stain to id. retics
What are the four common causes of microcytic anemia? What is the most common?
1) Iron deficiency*****
2) Anemia of chronic disease –esp. renal failure
3) Thalassemia
4) Siderblastic anemia
**This is the most common cause of microcytic anemia*
Recall, microcytic anemia= MCV less than 80 FL
What are the important lab values used to specifically evaluate microcytic anemia?
1) Serum iron
2) TIBC
3) % saturation
4) Serum ferritin**
How do you tell the difference between IDA and ACD?
See ppt.
What is hemolytic anemia?
Anemia caused by the destruction of blood cells
What are the causes of immune hemolytic anemia?
1) Drugs
2) Auto-immune disease e.g. SLE
3) Allo-immune
- Hemolytic transfusion rxn
- Hemolytic disease of newborn
What is the most common cause of autoimmune hemolytic anemia?
Systemic Lupus Erythematosus
What is the difference between the direct and indirect Coombs test?
DCT=
- Direct Antiglobulin Test (DAT)
- RBC
ICT=
- INdirect Antiglobulin Test
- Patient serum i.e. antibodies
Explain the DCT.
1) RBC sample from patient
2) Add anti-human antibodies (Coombs reagent)
3) Aggregation/ agglutination occurs indicating a positive test
Explain the ICT.
1) Obtain patient serum
2) Add donor (control) RBC
3) Patient Ig attack RBC
4) Add Coombs reagent
5) Agglutination indicates positive test
What is the difference between lymphoma and leukemia?
Lymphoma= lymphoid masses arising in discrete masses i.e. in a solid organ
Leukemia= lymphoid neoplasm with involvement of blood and bone marrow
- DOES NOT form a MASS
What cells are typically present in the germinal center of a lymph node?
asdf
What are the lab tests for diagnosing lymphoma?
1) Hematoxylin and Eosin (H&E)
2) Immunophenotyping= determining cell type via protein expression
- Immunohistochemistry
- Flow cytometry
3) Cytogenetics/ FISH= chromosomal abberations
4) Molecular diagnostics i.e. PCR
What is the key part of diagnosing lymphoma?
- Immunohistochemistry
- Flow cytometry
This is done to tell the difference between T and B cells
What are the symptoms of lymphoma?
1) PAINLESS, non-tender mass
2) Lymhadenopathy
3) Fatigue
4) Malaise
5) Night sweats
6) Fever
7) Weight loss
What is the difference between a diffuse and nodular lymphoma?
This is just the difference between the gross structure of a mass
What does polymorphic mean?
Cells are not of the same type
What is the origin of an immature lymphoid cell?
Lymphoblast
What is the origin of mature lymphoid cells?
Peripheral cells
What is the key marker for B-cells?
CD20
- CD19
- Lambda positive light chain
What is the key marker for T-cells?
CD3
What are the WHO characteristics for lymphoma classification?
- Clinical features
- Morphology
- Immunophenotype*****
- Cytogenetics
- Molecular analysis
What are the five main categories of lymphoma?
1) Precursor B-cell/ immature B-cell
2) Peripheral B-cell/ mature
3) Precursor T-cell/ immature T
4) Peripheral T-cell and NK cell/ mature T and NK
5) Hodgkin
Outline the staging of lymphoma.
I= single node, region, or extralymphatic site
II= 2+ regions on same side of diaphragm
III= BOTH sides of diaphragm
IV= Disseminated or diffuse involved
What is the difference between A and B stages of lymphoma?
Asymptomatic= A
Symptomatic= B
PET Scan example from powerpoint.
Stage III
What are the defining characteristics of Hodgkin Lymphoma?
Reed-Sternberg cells and variants
