Clinical Interpretations of Lab Exams

Question 1

What does anicoytosis mean?

Poikilocytosis?

Answer 1

Anisocytosis = size

Poikilocytosis = morphology

Question 2

What is the normal volume of RBC?

Answer 2

80-100 fL

Question 3

Macro vs Microcytic?

Answer 3

Macro = >100 fL

Micro = <80 fL

Question 4

How would you classify anemia?

Etiology vs MCV

Answer 4

Etiology –> Blood loss, Impaird Production, Increased Destruction

MCV -> Microcytic, Normocytic, Macrocytic

Question 5

What blood test would you order to investigate an anemic patient?

Answer 5

CBC

Question 6

CBC Components:

1. PCV
2. RBC Indices –> MCH and MCHC
3. RDW
4. TLC
5. Diff
6. PBS

Answer 6

PCV = Packed Cell Volume

MCH = Mean Corpuscular Hemoglobin

MCHC = Mean Corpuscular Hemoglobin Concentration

RDW = Red Cell Distribution Width

TLC = Total Leukocyte Count

Diff = Differential Leukocyte Count

PBS = Peripheral Blood Smear

Question 7

What does mean corpuscular volume help with?

Answer 7

Determining macrocytic vs microcytic anemias

Question 8

What is the normal range of WBC count?

Answer 8

4.0 to 11.0 K/uL

Question 9

What is the normal range of RBC count?

Answer 9

4.40 to 6.00 M/uL

Question 10

What is the normal range of Platelet count?

Answer 10

150 to 400 K/uL

Question 11

What should the relative percentages of Neutrophils, Lymphocytes, Monocytes, Eosinophils, and Basophils be?

Answer 11

Neutrophils 50 to 70%

Lymphocytes 20 to 40%

Monocyte 2 to 12%

Basophil < 1%

Eosinophil < 5%

Question 12

What is the normal range of Hemoglobin count?

Answer 12

Male –> 12 to 16 g/dL

Female –> 11 to 15 g/dL

Question 13

***What is the normal range of MCV?***

Answer 13

80 to 100 fL

Question 14

What is Reticulocyte Count (Retic Count) used for?

Answer 14

To assess erythropoietic activity

Question 15

What is ESR used for?

Answer 15

A non-specific characteristic that tells you whether the disease is active or not

Question 16

What is a Bone Marrow (BM) exam used for?

Answer 16

Used when cause of anemia is not evident

Question 17

Reticulocyte Count

1. Marker of
2. Normal Range
3. What to look for in Anemia

Answer 17

1. Marker of effective erythropoiesis (bone marrow response to anemia)
2. Normal range 0.5 to 1.5%
3. % count is falsely elevated in anemia

***Must be corrected for degree of anemia***

Corrected Retic Count = (Patient Hct/45) x Retic Count

Question 18

How are Reticulocytes detected in the blood?

Answer 18

Supravital stains - detect the thread-like RNA filaments in cytoplasm

Only remain in blood for 24 hours before becoming mature RBCs

Question 19

Microcytic Anemia (MCV < 80 fL)

What are the four types? (List in order of how common they are)

Answer 19

1. Iron Deficiency - Most Common
2. Anemia of Chronic Disease (ACD) - e.g. Kidney/Renal Failure
3. Thalassemia
4. Sideroblastic Anemia - Least Common

Question 20

What are some laboratory tests for microcytic anemias?

Answer 20

Serum Iron

TIBC (serum total iron binding capacity)

% Saturation [Serum Fe/TIBC] x 100

***Serum Ferritin –> Circulating fraction of storage iron (Single best test for iron studies)

Hb Electrophoresis (Gold standard for dx mild B-thalassemia; mild a-thalassemia is a dx of exclusion)

Question 21

Hemolytic Anemias

1. 3 Categories

Answer 21

1. Drug-induced
2. Autoimmune (Most Common; F > M)

***SLE most common cause of autoimmune hemolytic anemia (AIHA(

• 70% - Warm (IgG antibodies) type
• 30% - Cold (IgM antibodies + Complement) type
  3. Alloimmune
• Hemolytic Transfusion Reaction
• Hemolytic Disease of Newborn

Question 22

Direct Coombs Test (DCT)

(i.e. Direct Antiglobulin Test (DAT))

Answer 22

Uses patient RBC (has already contacted/touched with antibody) (Cell, rather than protein)

• Patient’s RBCs are incubated with antihuman antibodies (Coombs reagent)
• RBCs agglutinate: antihuman antibodies form links between RBCs by binding to the human antibodies on the RBCs

Question 23

Indirect Coombs Test (ICT)

(i.e. Indirect Antiglobulin Test (IAT))

Answer 23

Uses the patient’s serum or antibody directly (protein, rather than cell)

• Recipient’s serum is obtained, containing antibodies (Ig’s)
• Donor’s blood sample is added to the tube with serum
• Recipients Ig’s that target the donor’s RBCs form antibody-antigen complexes
• Anti-human Ig’s (Coombs Antibodies) are added to the solution
• Agglutination of RBCs occurs because human Ig’s are attached to the RBCs

Question 24

When would you use Indirect Coombs Test vs. Direct?

Answer 24

To test mother’s who are Rh negative to see if baby is Rh positive

Question 25

What does it mean if you see an increased percentage of **N****eutrophils**? **Lymphocytes**?

Answer 25

Increased Neutrophils --\> **Bacterial** infection Increased Lymphocytes --\> **Viral** infection

Question 26

Lymphoma

Answer 26

Lymphoid neoplasms arising in **discrete masses** (e.g. in _spleen_ or _lymph nodes_)

Question 27

Leukemia

Answer 27

Lymphoid neoplasms with involvement of the **blood and bone marrow** (usually no discrete masses)

Question 28

Answer 28

Normal Lymph Node

Question 29

Answer 29

Lymph Node - Germinal Center (Larger cells are the **macrophages**)

Question 30

What are used as tumor markers in lymphoma?

Answer 30

The various stages of **lymphocyte differentiation**

Question 31

**Lymphoma** 1. Tools for Diagnosis (4)

Answer 31

1. _Hematoxylin and Eosin_ (**H&E Stain**) 2. _Immunophenotyping_ (identifying **cell type** by protein expression) \*\*\***Critical** - only way to determine if coming from B- or T-cell - Immunohistochemistry - Flow Cytometry 3. _Cytogenetics/FISH_ (to identify **chromosomal aberration**) 4. _Molecular Diagnostics_ (PCR detect **monoclonal population** - **neoplastic lymphoid population**)

Question 32

What markers are looked for for **B cells**?

Answer 32

CD 19, 20, 21, 22 Occasionally **light chain** **(lambda) globulin**

Question 33

What markers are looked for for **T Cells**?

Answer 33

CD 2, 3, 4, 8

Question 34

What are the two methods used for **immunophenotyping**? (i.e. for determining if B- or T-cell origin)

Answer 34

Immunohistochemistry and Flow Cytometry

Question 35

What are important factors to understand as far clinical presentation?

Answer 35

Age Location Multiple/single site of involvement

Question 36

What does A or B mean about **lymphoma** stage? What are the symptoms?

Answer 36

A = Asymptomatic B = Sympatomatic - **PAINLESS**, Non-tender mass/lymphadenopathy - Fatigue - Malaise - Night Sweats (30% of patients) - Fever - Weight Loss

Question 37

What is the pattern of atypical proliferation? (i.e. diffuse, nodular, or both)

Answer 37

Diffuse

Question 38

What is the pattern of atypical proliferation? (i.e. diffuse, nodular, or both)

Answer 38

Nodular

Question 39

What are some critical considerations of **cellular morphology** of a lymphoma to consider as a pathologist?

Answer 39

Do all cells look **similar**? **monomorphic** Multiple cell types? **polymorphic** _Size_ _Nucleus_ (irregular, regular, round) _Chromatin_ (clumped, vesicular, open) _Cytoplasm_ (abundant/scant, color) _Mature (peripheral lymphoma) vs Immature (Lympho**blasts**)_

Question 40

Monomorphic vs Polymorphic

Answer 40

Question 41

**Lymphoma: Main Categories** 1. Precursor B-Cell Neoplasms 2. Peripheral B-Cell Neoplasms 3. Precursor T-Cell Neoplasms 4. Peripheral T-Cell and NK-Cell Neoplasms 5. Hodgkin's Lymphoma

Answer 41

1. Precursor B-Cell Neoplasms - **Immature B-Cells** 2. Peripheral B-Cell Neoplasms - **Mature B-Cells** 3. Precursor T-Cell Neoplasms - **Immature T-Cells** 4. Peripheral T-Cell and NK-Cell Neoplasms - **Mature T-Cells and Natural Killer Cells** 5. Hodgkin's Lymphoma - **Reed-Sternberg Cells and Variants**

Question 42

What are the main predominating tumors in people **under 10 years old** compared to **over 10 years old?**

Answer 42

\< 10 years old = **Acute Leukemia** \> 10 years old = **Lymphoma**

Question 43

\*\*\*Know this\*\*\* **Staging of Lymphoma** 1. Stage I 2. Stage II 3. Stage III 4. Stage IV 5. All stages - A vs B

Answer 43

I - **Single** lymph node _region_ or _extralymphatic site_ (I_E) II - **Two or more** LN regions or EL sites (II_E) on **same side** **of diaphragm** III - LN regions or EL sites (III_E) on **both sides of diaphragm** IV - **Disseminated** or **diffuse** involvement of one or more EL sites **_For all stages:_** A = Asymptomatic B = Fever, night sweats, or \> 10% weight loss