Clinical biochem 5 Flashcards
What are the 2 types of bone marrow? When are they converted?
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)
What do all cells begin as in hematopoiesis? what 2 things do they differentiate into ?
Begin as multipotential stem cell
- stem into myleoid or lymphoid
What are the steps for hematopoiesis from embryo –> adult
embryo: yolk sac
continue: spleen, liver, lymph nodes
3rd month fetal development: mostly liver
4th month of fetal development: bone marrow
Why is normal range of RBC in adult females lower than males? (2)
- Menstrual blood loss
- Higher androgen levels in men (erythropoietic)
What are drawbacks of RBC count?
Not useful to monitor qualitative changes in RBC
- iron deficient patient may have a normal number of RBCs with LOW Hgb/Hct
What is a hemoglobin test indicative of?
indicates oxygen carrying capacity of blood
- anemia = low oxygen carrying capacity
What is a hematocrit test indicative of? proportional to?
% of volume of blood composed of erythrocytes (RBC)
- proportional to hemoglobin
What does WBC count indicate? Low vs. High
of WBC but not type of WBC
Low: aplastic anemia, gram negative sepsis
High: infection, inflammation, hematologic melignancy, drug-induced
What does low vs high platelet count indicate?
Low: thromocytopenia, risks of spontaneous bleeding
High: risk of thrombosis (blood clot)
What is RBC Indices? What does it assess? What are the 3 tests?
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)
Explain mean corpuscular volume test MCV?
How is is calculated ?
What do normal, small, large volume of RBC indicate?
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
What may cause a falsely elevated MCV?
Reticulocytosis and hyperglycermia
Explain Mean Corpuscular hemoglobin MCH?
How is it calculated ?
What do normal, Low, high indicate?
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..)
What may cause a false elevation of MCH
Hyperlipidemia
Explain Mean Cell hemoglobin Concentration MCHC?
How is it calculated ?
What do decrease indicate?
when is it NOT increased?
indicates average Hgb concentration in the RBC
Calulcated: Hgb/ Hct
Decrease: iron deficiency, microcytic
NOT increased in pernicious (vit B12 deficiency anemia)
Explain Red Cell distribution width RDW indication?
Calculation?
What does an inc of RDW mean?
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
What is a reticulocyte?
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
What does a low and high Reticulocyte count RC indicate?
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)
What is the flow of RBC? How do you change that?
Normally they repel each other, settle slow
Adding acute phase reactants (fibrinogen) –> induce a positive charge –> RBCs aggregate and settle faster (make rouleux)
What is the test for RBC settling? What is it used for? What is the correction for age/gender for this test?
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
What are conditions that can increase and decrease ESR
Increase ESR
- age
- female
- infection
- inflammation
- Macrocytic anemia (high volume of RBC)
decrease ESR
- heart failure
- microcytic anemia
- sickle cell anemia
- corticosteroids
What do myeloid cells function as?
Phagocytes
What do granulocytes function as?
Defense against bacteria
What do lymphoid cells function as?
give specificity and memory to the body’s defense against foreign invaders
Define the term demargination
Rapid increase in mature cells (infection) in the blood stream due to liberation of the marginated pool (staying along blood vessel wall)
What is a band neutrophil? Explain left shift
Curved nucleus and immature neutrophil not seen in the bloodstream.
- inc in number of bands in bloodstream
What happens during an infection with neutrophils?
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
Explain neutropenia.
Low neutrophils in body
What are causes of Neutrophilia and neutropenia
Neutrophilia 12,000+
- acute + chronic bacterial infection
- myocardian infraction
- leukemia
- Drugs: epinephrine, corticosteroids, lithium
Neutropenia <1500
- overwhelming infection
- B12 / folate deficinecy
- Pertussis
- Salmonellosis
- Drugs
What is eosinophils used for?
- in intestinal mucosa and lungs
- phagocytize, kill, and digest bacteria
- provide defense against parasites
- involved in hypersensitivty reactions
Causes of eosinophilia vs eosinopenia
eosinophilia 350+
- allergic disorders
- asthma
- parasitic infection
- Leukemia
- Meds: ACE inhibitors, allergy to a drug
eosinopenia <50
- acute infection
What do Basophils contain? what are they involved in?
Contain: heparin, leukotriene and histamine
Involved in acute and late phase hypersensitivity
Explain function of monocytes
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
Cause of basophilia 300+ (high)
Acute infection
Cause of monocytosis (high)
- Recovery stage of acute bacterial infection
- Disseminated TB
- Endocarditis
- Protozoal infection
- Rickesttsial infection
- Leukemia
What are T cells and B cells for?
T cells: cell mediated immunity
B cells: recognition of foreign substances
What are causes of lymphocytosis and lymphocytopenia
lymphocytosis 4000+
- infectious mono
- viral infections
- tuberculosis
- syphilis
lymphocytopenia <1000
- HIV
- Radiation exposure
- Corticosteroids
- Aplastic anemia
