Collection of blood and anticoagulants

1. Collection of Blood
&
Anticoagulants

2. BIOHAZARD PRECAUTIONS
Universal precautions:
 The operator should wear disposable plastic or
thin rubber gloves.
 Care must be taken to prevent injuries, especially
when handling syringes, needles and lancets.
 Do not recap used needles
 Disposable sterilized syringes, needles and
lancets should be used if at all possible, and they
should never be re-used.
 All sharps discarded in puncture resistant plastic
sharps container

3. Type of
sample
Usual sites Uses
Capillary - Ear lobes
- Distal digit of 3rd / 4th
finger
-Heel, Big toe - in infants
-PS, Hemoglobin,
Blood grouping
-Reagent strips
Venous blood -Cubital vein,
-Dorsum of the hand
-When large amount of
blood is needed
-For transportation
Arterial blood -Carotid artery
-Femoral artery
Blood gas analysis

4. Capillary blood
 PCV, RBC count & Hb
concentration are
slightly greater
 Total WBC & neutrophil
counts are higher by
about 8% and
monocyte count by
about 12%
Venous blood
 Platelet count appears
to be higher by 9%-
32%.
 This may be due to
adhesion of platelets to
the site of the skin
puncture.

5. FINGER PRICK

6. Indications of finger prick
 Small amount of blood needed
 When venepuncture would be too invasive
 Poor veins not suitable for a venepuncture
 The patient has only one good vein that must be
saved for another procedure
 Extremely apprehensive patients
 Extensive scar tissue, bruising, obesity and other
physical features

7.  It should be from the non-dominant hand
 Arm held in the anatomical position and the hand
below the heart.
 Earlobes, for example only have few capillaries
 Heel areas - exclusively for neonates & younger
infants.
 Heels & toes are not the sites of choice in adults-
extremely calloused and tough.

8.  SITE OF CHOICE: The distal lateral aspect of
middle or ring finger in adults & children

9.  If the patient's hands are cold - warmed by
holding them under warm running water or by
briskly rubbing them.
 The patient may be asked to wash the hands with
warm soap water – cleanse, soften the skin &
effectively increase the blood flow to the fingers.

10.  Massage the finger from hand to tip 5- 6 times to
increase the blood flow.
 This manoeuvre can be best described as gently
milking the finger -- not squeezing it! However,
be careful not to over-do it
 It may cause erroneous results due to
concentration of tissue fluids.

11.  Cleanse the selected fingertip with 70% isopropyl
alcohol to remove all dirt, sweat, lotions, and
invisible micro organisms.
 Wipe dry with a clean, dry piece of gauze or
cotton.
 Before piercing be sure that the finger is
thoroughly dry.

12.  With a quick stabbing wrist motion make a
puncture wound 2-3 mm deep on the lateral
aspect of the ball of the finger using a LANCET
- avoids the nerves of the fingertip -- avoids
unnecessary pain
 The cut should be perpendicular to the lines in
the fingerprint so that the blood will form a drop.
(Parallel puncture will allow blood to run down the
finger)
 Free flow of large drops slowly & spontaneously
 First drop discarded

13.  Holding the finger lightly, fill a (heparinized)
capillary pipette or other collecting device.
 The capillary pipette should be held in an almost
horizontal position with the tip touching the drop
of blood.
The tube should not be allowed to touch the
finger.
 Should more blood be needed, a small test tube
or commercial micro tube may be held beneath
the finger and blood dropped into it.

14.  When sufficient blood has been obtained, place a
clean, dry gauze pad or cotton ball over the site
and have the patient press with the thumb on the
same hand until bleeding has stopped.
WASTE DISPOSAL
 Discard used lancets (and needles) in a ‘puncture
resistant sharps bin’.
 Drop used capillary tubes, contaminated swabs
and tissues and all non-sharp materials into a
biohazard bag.

15.  Disadvantages
– Dilution with body fluids
– Activation of platelets
– Small amount of blood
– Squeezing to express blood cause erroneous
results

16. VENEPUNCTURE

17.  SITES – antecubital vein, femoral vein in infants
 PROCEDURE
– 19-21G needles used
– Clean area with 70% alcohol
– Tourniquet or sphygmomanometer applied to
upper arm
– Introduce needle at 15° to skin surface
– Stabilize vein & introduce in to vein
– Loosen tourniquet when needle is inside
– Withdraw piston according to rate of filling of
vein
– Detach needle & deliver to container with
anticoagulant

18. Detailed Venepuncture procedure
 Clean puncture site with an appropriate antiseptic
(Betadine or 70% isopropyl alcohol) using
circular motion towards the periphery.
 If phlebotomy site must be palpated again it can
only be done with one finger that was cleansed
with alcohol before touching to feel the vein.
 Apply tourniquet around arm 3-4 inches above
Venepuncture site.
 Do not leave tourniquet on the arm for more than
1-2 minutes.

19.  Grasp patient's arm firmly, placing the thumb 1-2
inches below the chosen site to draw skin taut.
 This will anchor the vein.
 If possible, make sure the patient's arm is in a
downward position. This will help ensure that no
back-flow from the tube will go into the patient's
arm.
 Perform Venepuncture entering the vein keeping
bevel side of needle up.

20.  Grasp barrel of syringe firmly and pull firmly on
plunger until required amount of blood is in the
syringe.
 At the completion of the Venepuncture,
immediately after the needle is removed from the
vein apply direct pressure to puncture site.

21.  Containers
– Glass or plastic test tubes
– Silicon coated tubes( coagulation studies)
– Evacuated tube systems
 Precautions to prevent hemolysis
– Clean &dry apparatus
– Fine bore needles should not be used
– Blood withdrawn slowly
– Mix gently with anticoagulant
– Detach needle before expressing to container

22. Vacutainer® Blood Collection System
(Vacutainer is a registered trademark of Becton, Dickinson and Company)
 Vacutainer® Needle has a sharp
point at both ends, and usually is
covered by a rubber sheath, with
one end being shorter than the
other.
 The long end of the needle is used
for penetrating the vein
 The shorter end is used to pierce the
rubber stopper of the vacuum tube.

23. Vacutainer® Holder
 is a plastic sleeve into which the phlebotomist
screws the double pointed Vacutainer® needle.
Vacutainer® Tubes
 Are glass tubes sealed with a partial vacuum
inside by rubber stoppers.
 The colour of the top of the vacutainer tube
indicates the type of anticoagulant inside the tube
– Red – No anticoagulant for serum collection
– Green – Heparin
– Purple – EDTA
– Gray- fluoride

30. No anticoagulant- clot activator —
serum – biochemistry
EDTA– for ESR, Routine hematology
Lithium or Sodium Heparin
Pot. Oxalate & sodium Fluoride–
Blood glucose
Sodium citrate – PT, APTT,INR

32. ANTICOAGULANTS

33.  CALCIUM CHELATORS
– EDTA
– Citrate
– Oxalates
 HEPARIN
– Acts via antithrombin III

34. Anticoagulant Amount Uses Disadvantage
Na+ or K+ EDTA 1.2 mg/ml Blood RE
TRI SODIUM
CITRATE
3.8gm%
1:4 ratio---
1:9 ratio---
ESR
Coagulation
tests
Dilutes the blood, so
not used for cell
counts / Hb
DOUBLE OXALATE
( Wintrobes
mixture)
Ammo.–1.2 gm
Potass.- O.8 gm
Dist.water-100ml
2mg/ ml Blood RE PS-background
staining
HEPARIN
Activate
Antithrombin-III
15 iu /ml Osmotic
fragility
-Expensive
- Not good for smears

35.  What are the effects of storage on blood cell
morphology?
 What are the quantitative effects of storage on
blood/time limit within which various tests are to
be performed?
 What are the effects of excess anticoagulant on
blood cell morphology?

36. Effects of storage on blood cell counts
 In few hours, RBC
swells - increased
PCV, MCV & OF with
reduced ESR
 Platelet count falls in
2hrs
 Reticulocytes –
unchanged for 24 hr if
kept at 4°C
-- reduced by 6 hr if
at room temp
 Prolonged
coagulation times
Counts relatively stable if blood stored at 4°C
After 2-3 days, blood lyses – PCV and RBC count
reduces with increase in calculated MCH &
MCHC

37. Effects of storage on blood cell morphology
 Swelling of RBC - spherocytes
 Crenation of RBC
 Autolysis and disintegration of WBC

38. OUTER TIME LIMITS
 2hr- PT, PLT count, peripheral smear
 3hr –ESR
 24hr- RBC count, Hb, PCV,WBC count,
Reticulocyte count

39. Effects of excess anticoagulant on blood
cell count & morphology
EDTA-
 Decrease in PCV
 Increase in MCHC
 Platelet swell &
disintegrate- high
platelet count
 Fall in WBC count on
storage
 Crenation of RBC &
degenerative changes
of WBC
 Leucoagluttination
 Fail to demonstrate
basophilic stippling
HEPARIN- leukocyte clumping (not suitable for
cell counts)

40. Thank you