Blood Flashcards
stats for:
how much rbc?
how effective?
how large
shape?
lifespan?
f?
- 4.4 -5.9x10^12/L
- Hb = 13.5-16.7 g/dL
- MCV mean corpuscular volume) 80-100fl
- biconcave flexible disc -~8microm diameter
- 120 days
- deliver oxygen to tissues , carry Hb, maintain Hb in its ferrous (reduced state), maintain osmotic equlibirum and generate energy
what causes RBC shape changes? and what does this causes?
name 1 condition
- changes to the components of the membrane
- causes them to become more fragile and less deformable, so spleen recognises them as abnormal and takesn them up, which cancause haemolytic anemia
- spherocytosis
what is the structure of erythrocyte structure?
- Ankyrin ; spectrin, band 3 and 4.2
What are the instruments, and turn over time for UHL haem labs?
- 9 FBC analysers , 6 coagulation analysers
- URGENT (A&E) 1 hour
- Non-urgent (ward patients)
normal vs abnormal results
what affect normal results
- normal ranges = 95% of healthy population levels, but not everyones falls into the catergory, what you do is multiple tests and see if theres a drop, that would be abnormal
- gender, sex, ethnicity, co-morbidities
why do we get abnormal b results?
- due to issue or reactionof the blood (EDTA)
what errors can occur in;
- specimen collection
- delivery of specimen to lab
- specimen analysis and result reporting
- responsive action
- specimen mix up/ Wrong blood in tube(WBIT) / pooling of sample (combinined fluids like urine and blood) / poor technique
- delayed specimen/not delievered/wrong delivery method
- specimen mix up/ incorrect clinical details/wrong test performed/inherent test variability/technical error
- result not reviewed/reflex tests not carried out(reflex tests =additional tests)/right result applied to wrong patient
what are essential parameters of FBC?
what analysis techniques used?
- platelets / RBC /Hb/ WBC
- spectrophotometry ; (amount of light abosred by sample proportional to amount of absorbant compount within ite.g used to meaure Hb. it isues hypotonic solution to lysis cells and release Hb, then use light as the wavelength and use calibration curve to determine the sample concentration)
- Flow Cytometry ; involves cells in single line and light baem passing through, forward scatterng = size. and side scatter =whether mono/polymorphonuclear, or inreaceullar complexities like granules) can check myeloperoxidase activity = important in inflammation detection
PCV?
why used?
why shouldnt you always trust polycythenia results?
- packed cell volume aka haematocrit (L) allows you to see what proportion of blood allows visualisation
- used to assess anaemia and polycythemia
- pseudo polycythenia due to less water = less plasma so higher haematocrit
hb levels for
men
women
children 3-puberty
newborns
>135g/L
>115g/L
>110g/L
>150g/L
whats in vitro vs in vivo haemolysis?
what do they cause
- in vitro= haemolysis due to cellulr damage
- in vivo = RBC haemolysis due to increase in erythrocyte destruction rate or decreased erythrocyte life span
- reduced Hb
why do a RBC specifically? RCC of examples fo each
to test for anaemia and erythrocytosis (body makes ^RBC which can rsult in polycythesia)
- microcytic anaemia (RBCunsually small) ; iron deficiency anaemia = lower RBC because smaller RBC less Hb so less iron // thalassemia triat = higher RCC because lots of RBC but have defective hb
how do we measure size of RBC?
lighter scattered as they pass in a single fine past a laser
causes of anaemia
- megalablastic anaemia (vitB12, folate) = iron deficeny anaemia
- liver disease
what’s increased mean cell haemoglobin conc (g/L)
and why do we do it?
^ = spherocytosis (mishaped RBC si bone marrow makes more ‘normal’RBCsooverall higher PCV and higher MCHC
- most important test to identify of cold aggultinins (antibodies produced by body that target RBC and aggregate them together increasing risk of them being destroyed so increased number od cold aggulins = decreased RBC = decreased MCHC) caused by viral/mycoplasma infections
whast RCDW? ^ levels? why do we do it?
red cell distribution width = variation in sizeof RBC
anisocytosis (pateints RBC sized are unequal)
used to assess causes of anaemia = increased in iron deficiency especially in nutrients like folate, v12 deficeiency because they are larger) / usually ormal in thalassemia trait / increased flowing transfusion
whast rc adn unit? how is it indentified?
reticulocyte count
measurement of the number of young erythrocytes
identified using size and RNA content
what’s a blood film and why use it?
what do you need to consider with it?
- only do it if sample is plagged so if significant results or change really out of nomral range
takes longer to get results
what is a blood sample placed in and why?
- blood tube containing EDTA because it contains ca2+ wc mixes with the blood and chelates it acting like an anticoagulant, without itthe blood would clot
what should you do with a UE analysis of blood?
neverpour it from the FBC b test tube, because there’s k+salt in EDTA wc will c a high k+ reading
How is WBC measured
-automatatic counting involved a ligth beam, but first it has to be lysed out from RBC sample
how is RBC count done
-same as WBC so with autated interrupted beam of light or electrical current tht counts them as they move as a line through a narrow tube)
how do you measure Hb conc
amount of Hb g/L
- lysis of RBC and then convert Hb to astable form then carry out spectrophotometry
HCT
what has changed now?
haematocrit
- fraction of whole blood that consists of RBC only
- measured vi a centriduge, you would get the PCV (packed cell volume - so height of haematocrit, but that has been replaced by another calcualtion;
MCV (mean corpuscle volume; averagesize of RBC) x numer of RBC per litre to give haematocrit
MCV
mean corpusclar volume
average red blood volume measured in femtolitres (10^15)
- useful in determining macrocytic and microcytic anaemia
MCH
mean cell hb
- average amount of Hb (measured in pg (10^-15kg) in 1 RBC
so do this by ; Hb in given volume/ umberof rBC in given volume
platelets count
- same analyser but smaller signal because its smaller
Reticulocyte count
- immature RBc releaed into blood,
- reticulotey/Hct %
- good for distinugishingif the bone marrow is wrking or not
what’s a blood film
blood smear to check the shape of RBC
- dropof blood, thinly then dispersed used a spreder slide to make sure ,onolayer of cells then viewed under microscope, dried in methanol
- used for aprastites, shapes of RBC, count physical WBC/RBC adn for cell abnormlaits like membrane defects, thrombotic thrbocytopenic purpura
thrombotic thrombocytopenia purpura
-b clots in small vessels c thrombocytopenia
low MCV?
microcytic anaemia ( TAILS)
<80fl (10^-15 litres)
high MCV
macrocytic (nomegaloblastic ; liver disease, alcoholism, diamond-blackfan anaemia ) OR megaloblastic ;Vit B12/ folate deficency , or orotic anaemia (orotic acid is a mineral carrier),or defective DNa repair (Fanconi aneamia ; cant repair damagedDNA)
low MCH
- microcytic (TAILS)
- dont do this for macro nomegaloblastic anaemic b it has normal hb just ^ cell d ^ lipid in mitochondira
