Blood cell parameters

Question 1

importance of parameters

Answer 1

diagnose and follow treatment of leukaemia, infections etc

define presence, types and therapeutics of anaemia - from RBC

Question 2

why RBC

Answer 2

simple
most concentrated cell in blood
unique morphology - don’t need staining or mechanical separation

Question 3

haematocrit

Answer 3

the relative vol of blood sample that is RBC

Question 4

significance of RBC parameters

Answer 4

in diagnosis - extended to other cell types

Question 5

safety precautions

Answer 5

clean skin with alcohol swab 
don't share needles 
dispose in sharps bin 
protect wound with plaster 
wear lab coat 
protective gloves 
wash hands if contact blood 
never use mouth pipette 
decontaminate spills

Question 6

venepuncture process

Answer 6

collect equipment 
open package of needle 
connect vacutainer hub to the needle 
get tourniquet and wipe ready 
choose appropriate vein - normally antecubital fossa on elbow joint  
put on tourniquet 
alcowipe 
hand gel again 
gloves - invasive part 
take off cap over needle 
flat side into vein - 45 degrees  - hold by wings 
don't palpate vein 
want flashback in canister 
vacuum work when put blood bottle on 
bottle will fill 
take it off
then invert 
release tourniquet 
take needle out and put yellow cap over 
gauze and tape over pt 
write details at bedside

Question 7

ANNT

Answer 7

aseptic non-touch technique

Question 8

why do blood bottles contain EDTA

Answer 8

anticoagulant
stop clotting
so can be manipulated

Question 9

why do you need inversion

Answer 9

cells denser than plasma so settle at bottom

Question 10

sample prep

Answer 10

prepare blood on parafilm

use Pasteur pipette - draw small amount and drop 7-10 drops

Question 11

RBC count

Answer 11

dilute blood 200 fold
place on 0.11mm thick ruled haemocytometer slide
red cells fall on ruled area - calculating those in known area number cells in 1L blood calculated

Question 12

what happens if white cells are counted in RBC count

Answer 12

negligible - 500 RBC to 1 WBC

Question 13

diluting the blood

Answer 13

5ul blood added to 995ul isotonic saline soln
blood sampled with capillary pipette
place 5ul capillary pipette into cap pipette holder
place open end into blood at shallow angle and allow pipette to fill
transfer to saline by putting finger over air hole and squeezing bulb

Question 14

capillary pipette

Answer 14

hole to allow capillary attraction 
rubber teat 
glass tube 
plastic seal 
capillary tube of known vol

Question 15

measurements from a haemocytometer slide

Answer 15

improved Neubauer - central portion depressed and kie 0.1mm below glass cover
incorporates calibrated ruled area
rulings define central square - 1mm sides into 25smaller squares 0.2mm sides
divided into 16 squares with 0.05mm sides
count in 5 medium non-adjacent squares - total vol of 0.02mmcubed = 0.00001mmcubed undiluted blood
number of cells multiplied by 10(power4) for RBC in 1mmcubed and 10(power10) RBC in 1L

Question 16

counting cells at the edge

Answer 16

edge convention

cells touching bottom and R are counted - rest are not

Question 17

using a haemocytometer

Answer 17

place coverslip on haemocytometer slide
leave small section exposed at outer edge
use Pasteur pipette and pick up a small amount - touch one drop on slide
suspension will fill gap between cover slip and slide - capillary tension
examine cells on 4x or 10x
if uneven/air bubbles - new preparation must be made on the slides

Question 18

expressing the number of RBC in 1L

Answer 18

Nx10(power10)/L
more commonly
(N/100)x10(power12)/L

Question 19

preparing the haemocytometer

Answer 19

exhale on it - mist up
place slide over and push to front
use Pasteur pipette and drop blood onto haemocytometer

Question 20

using the capillary pipette

Answer 20

put finger over hole to draw up blood into tube
remove finger
to remove blood from the tube - replace finger and squeeze the rubber teat