Clinical biochem 5

Question 1

What are the 2 types of bone marrow? When are they converted?

Answer 1

Red bone marrow: produce red blood cells
Yellow bone marrow: mainly composed of fat
- 50% of red converts to yellow marrow by adulthood
- Body can convert yellow to red during times of need (anemia)

Question 2

What do all cells begin as in hematopoiesis? what 2 things do they differentiate into ?

Answer 2

Begin as multipotential stem cell
- stem into myleoid or lymphoid

Question 3

What are the steps for hematopoiesis from embryo –> adult

Answer 3

embryo: yolk sac
continue: spleen, liver, lymph nodes
3rd month fetal development: mostly liver
4th month of fetal development: bone marrow

Question 4

Why is normal range of RBC in adult females lower than males? (2)

Answer 4

• Menstrual blood loss
• Higher androgen levels in men (erythropoietic)

Question 5

What are drawbacks of RBC count?

Answer 5

Not useful to monitor qualitative changes in RBC
- iron deficient patient may have a normal number of RBCs with LOW Hgb/Hct

Question 6

What is a hemoglobin test indicative of?

Answer 6

indicates oxygen carrying capacity of blood
- anemia = low oxygen carrying capacity

Question 7

What is a hematocrit test indicative of? proportional to?

Answer 7

% of volume of blood composed of erythrocytes (RBC)
- proportional to hemoglobin

Question 8

What does WBC count indicate? Low vs. High

Answer 8

of WBC but not type of WBC

Low: aplastic anemia, gram negative sepsis
High: infection, inflammation, hematologic melignancy, drug-induced

Question 9

What does low vs high platelet count indicate?

Answer 9

Low: thromocytopenia, risks of spontaneous bleeding

High: risk of thrombosis (blood clot)

Question 10

What is RBC Indices? What does it assess? What are the 3 tests?

Answer 10

Calculated (indirect) measures of RBC morphology used to help in differential diagnosis of anemia

Assess: size and hgb content of RBC

Tests:
Mean corupuscular volume (MCV)
Mean cell hemoglobin (MCH)
Mean cell hemoglobin concentration (MCHC)

Question 11

Explain mean corpuscular volume test MCV?
How is is calculated ?
What do normal, small, large volume of RBC indicate?

Answer 11

Volume size of RBCs
Calculated: Hct/ RBC count

Normal: normocytic
Small: microcytic
- iron deficiency, thalassemias
Large: Macrocytic
- liver disease, alcoholism, antimetabolite theraoy, folate/B12 deficiency, valproate therapy

Question 12

What may cause a falsely elevated MCV?

Answer 12

Reticulocytosis and hyperglycermia

Question 13

Explain Mean Corpuscular hemoglobin MCH?
How is it calculated ?
What do normal, Low, high indicate?

Answer 13

Average weight of Hgb in the RBC
Calculated: Hgb/RBC

Normal: normochromic
Low: Hyprochromic
- iron deficiency anemia
High: hyperchromic
- macrocytic (large volume of RBC; liver disease etc..)

Question 14

What may cause a false elevation of MCH

Answer 14

Hyperlipidemia

Question 15

Explain Mean Cell hemoglobin Concentration MCHC?
How is it calculated ?
What do decrease indicate?
when is it NOT increased?

Answer 15

indicates average Hgb concentration in the RBC
Calulcated: Hgb/ Hct

Decrease: iron deficiency, microcytic
NOT increased in pernicious (vit B12 deficiency anemia)

Question 16

Explain Red Cell distribution width RDW indication?
Calculation?
What does an inc of RDW mean?

Answer 16

Indication of variation in RBC volume (size)
- Coefficient of variation of the MCV

RDW = (SD of MCV / mean of MCV) x 100

High RDW = unequal sized RBCs
- used to confirm mixed anemia

Question 17

What is a reticulocyte?

Answer 17

An immature RBC that is still capable of RNA production
- once released into blood, matures into RBC in 1 day
- larger than a mature RBC

Question 18

What does a low and high Reticulocyte count RC indicate?

Answer 18

Low: bone marrow suspension
Rapid rise: Monitor response to anemia
- in anemia total RBC are reduced, so RC will appear high in anemia (even though RC is normal)

Question 19

What is the flow of RBC? How do you change that?

Answer 19

Normally they repel each other, settle slow

Adding acute phase reactants (fibrinogen) –> induce a positive charge –> RBCs aggregate and settle faster (make rouleux)

Question 20

What is the test for RBC settling? What is it used for? What is the correction for age/gender for this test?

Answer 20

Test: Erythrocyte Sedimentation rate
Westergen test

Used:
- confirm diagnosis supported by other tests
- monitor activity of inlammatory conditions

Men: age/2
Women: age + 10 / 2

Question 21

What are conditions that can increase and decrease ESR

Answer 21

Increase ESR
- age
- female
- infection
- inflammation
- Macrocytic anemia (high volume of RBC)

decrease ESR
- heart failure
- microcytic anemia
- sickle cell anemia
- corticosteroids

Question 22

What do myeloid cells function as?

Answer 22

Phagocytes

Question 23

What do granulocytes function as?

Answer 23

Defense against bacteria

Question 24

What do lymphoid cells function as?

Answer 24

give specificity and memory to the body’s defense against foreign invaders

Question 25

Define the term demargination

Answer 25

Rapid increase in mature cells (infection) in the blood stream due to liberation of the marginated pool (staying along blood vessel wall)

Question 26

What is a band neutrophil? Explain left shift

Answer 26

Curved nucleus and immature neutrophil not seen in the bloodstream.
- inc in number of bands in bloodstream

Question 27

What happens during an infection with neutrophils?

Answer 27

Neutrophilia:
High number of neutrophils due to demargination (NOT A LEFT SHIFT)

left shift occurs after due to the amount of immature cells being released (bands) to replace demarginated cells and fight acute infections

Question 28

Explain neutropenia.

Answer 28

Low neutrophils in body

Question 29

What are causes of Neutrophilia and neutropenia

Answer 29

Neutrophilia 12,000+
- acute + chronic bacterial infection
- myocardian infraction
- leukemia
- Drugs: epinephrine, corticosteroids, lithium

Neutropenia <1500
- overwhelming infection
- B12 / folate deficinecy
- Pertussis
- Salmonellosis
- Drugs

Question 30

What is eosinophils used for?

Answer 30

• in intestinal mucosa and lungs
• phagocytize, kill, and digest bacteria
• provide defense against parasites
• involved in hypersensitivty reactions

Question 31

Causes of eosinophilia vs eosinopenia

Answer 31

eosinophilia 350+
- allergic disorders
- asthma
- parasitic infection
- Leukemia
- Meds: ACE inhibitors, allergy to a drug

eosinopenia <50
- acute infection

Question 32

What do Basophils contain? what are they involved in?

Answer 32

Contain: heparin, leukotriene and histamine
Involved in acute and late phase hypersensitivity

Question 33

Explain function of monocytes

Answer 33

Function: macrophages
- removal of foreign substance
- destruction of old RBCs
- salvage iron from old RBCs and return it to transferrin for delivery to bone marrow

Question 34

Cause of basophilia 300+ (high)

Answer 34

Acute infection

Question 35

Cause of monocytosis (high)

Answer 35

• Recovery stage of acute bacterial infection
• Disseminated TB
• Endocarditis
• Protozoal infection
• Rickesttsial infection
• Leukemia

Question 36

What are T cells and B cells for?

Answer 36

T cells: cell mediated immunity
B cells: recognition of foreign substances

Question 37

What are causes of lymphocytosis and lymphocytopenia

Answer 37

lymphocytosis 4000+
- infectious mono
- viral infections
- tuberculosis
- syphilis

lymphocytopenia <1000
- HIV
- Radiation exposure
- Corticosteroids
- Aplastic anemia