Hema 2 Lab Module 3: Bleeding Time, Capillary Fragility, Clot Retraction

Bleeding Time

- In vivo measurement of the platelet adhesion function

- Also measure aggregation to a locally injured subendothelium or vascular sub-endothelium

- Initial test for patients suspected of having congenital platelet abnormality or von Willebrand Disease (vWD)

- von Willebrand Factor

- GP Ib/IX complex

- Platelet must have the capacity to aggregate with each other

In order for adhesion to occur, it needs the presence of:

- Plasma von Willebrand Factor Deficiency

- Abnormalities in the vessel wall of the patient

(BLEEDING TIME)

Sensitive to the abnormality of the platelet numbers and function:

- Ask patient if they are taking any medication

- Inform patient of possible scarring or keloid formation

Before starting the procedure for bleeding time:

Aspirin

Medication that inhibits cyclooxygenase activity which leads to inhibition of Thromboxane-A2

1 week

Patients taking aspirin are asked to discontinue ingestion for______ prior to test

NSAIDS

- Non-steroidal anti-inflammatory drugs

- Ibuprofen

- Naproxen

24 hours

Patients taking NSAIDS are asked to discontinue ingestion for______ prior to test

Duke Method

Considered to be an obsolete method - not precise and accurate

Duke Method

Materials: Feather Lancet

Site of Puncture: Earlobe or Fingertip Incision

Size Lancet: size-dependent

Normal Value: 5 minutes

1 puncture - earlobe / fingertip

Blot every 30s

How many punctures will be done in the Duke Method? And you will blot every how many seconds?

Whatman filter paper #3

What is the name of the filter paper used in Duke Method?

Ivy Method

Has a modification and/or advantage - application of a blood pressure cuff

40mmHg

Blood pressure cuff pressure is maintained at ______ for Ivy Method

Ivy Method

Materials: Feather Lancet with BP cuff (40mmHg)

Site of Puncture: Volar surface of the forearm 5cm below the antecubital crease (Free of veins, scars, bruise, hairs, and swelling)

Incision Size: Parallel to the antecubital crease

Lancet: size-dependent

Normal Value: 2.5-7 minutes

2 punctures - forearm

How many punctures in the Ivy Method?

NV: 1-6 mins (AVE. 3- 5 mins)

Normal value for Ivy Method

15

(Ivy Method)

After ____mins if still bleeding, discontinue test and report it as prolonged

Elbow fold

(Ivy Method)

Cut must be parallel to

Template Method

This method was modified by Melke et. al

Template Method (Modified Ivy Method)

The template method is a modified version of what method?

40 mmHg

Blood pressure cuff pressure is maintained at ______ for Template Method

Volar surface of the forearm 5cm below the antecubital crease (or fold of the elbow) (Free of veins, scars, bruise, hairs, and swelling)

Site of Puncture for Template Method

Parallel & Perpendicular

What are the 2 incision directions for template method?

Parallel

Name the incision direction: (Template Method)

>More sensitive

>Tends to prolong bleeding time

>Most commonly used

Perpendicular

Name the incision direction: (Template Method)

Produce less scar formation

Only do wicking ( to not disturb primary platelet plug formation)

(TEMPLATE METHOD)

T/F: Blot incision site with filter paper (whatman filter paper #3), touching of the incision site is suggested

Simplate Device

(TEMPLATE METHOD)

Name the template device and method:

- Guillotine-like cut

- Blade won't retract

- One blade or two blade

- 2 springs loaded with blades - 5mm long, 1mm deep and 1cm apart

- Blot every 30s

- NV: 2.3-9.5 mins

Surgicutt Device

(TEMPLATE METHOD)

Name the template device and method:

-Slicing action

-Blade automatically retracts

- 5mm long, 1mm deep

- Should not make a depression on skin - false high BT

- NV: 1.8-8 mins

Pedia

Pink colored surgicutt device

White

White colored surgicutt device

20 mmHg

( BP CUFF PRESSURE FOR NEWBORNS AND CHILDREN)

<2lbs

25 mmHg

( BP CUFF PRESSURE FOR NEWBORNS AND CHILDREN)

2-4 lbs

30 mmHg

( BP CUFF PRESSURE FOR NEWBORNS AND CHILDREN)

>4 lbs

Prolonged

Expected finding of bleeding time for patients with anemia

(Decreased, Prolonged)

<100,000 cells/uL

Thrombocytopenia - ________ cells/uL = prolonged BT

Antibiotics - penicillin, cephalothin

Antibiotics that can affect the bleeding time:

Prolonged

Expected finding of bleeding time for patients with vWD

(Decreased, Prolonged)

Prolonged

Expected finding of bleeding time for patients with Glanzmann thrombasthenia

(Decreased, Prolonged)

Prolonged

Expected finding of bleeding time for patients with Bernard-soulier syndrome

(Decreased, Prolonged)

Qualitative platelet defect - platelet aggregation

Glanzmann thrombasthenia is a _______(qualitative, quantitative) defect that affects platelet _______(adhesion,aggregation)

GP IIb/IIIa complex deficiency

Glanzmann thrombasthenia is deficient in?

Qualitative defect - GP Ib/IX complex deficiency (vWF receptor)

Bernard-soulier syndrome is a _______(qualitative, quantitative) defect that affects platelet _______(adhesion,aggregation)

HermanskyPudlak Syndrome

Congenital storage pool disease

CAPILLARY FRAGILITY TEST

Uses POSITIVE PRESSURE

(TOURNIQUET TEST / RUMPEL-LEEDE TEST)

other name for CAPILLARY FRAGILITY TEST

CAPILLARY FRAGILITY TEST

Detects the ability of the small blood vessels to retain RBCs in their lumen under conditions of stress and trauma

petechiae formation

CAPILLARY FRAGILITY TEST POSITIVE RESULT

Petechiae

minute hemorrhages in the skin near the site where pressure is applied. Indicates bleeding in the skin

Thrombocytopenia

Decreased fibrinogen

Vascular purpura

Disease that cause POSITIVE TOURNIQUET TEST

TOURNIQUET TEST / RUMPEL-LEEDE TEST

Materials Stethoscope and BP cuff; Apply BP cuff for 5 minutes maintained at 80mmHg pressure

7 days

In RUMPEL-LEEDE TEST do not repeat test on the same arm within how many days to avoid false positive

Negative

Reporting for RUMPEL-LEEDE TEST: <10 fresh petechiae

Borderline

Reporting for RUMPEL-LEEDE TEST: 10-20 fresh petechiae

Positive

Reporting for RUMPEL-LEEDE TEST: >20 fresh petechiae

ELLIOT METHOD

-NEGATIVE PRESSURE

-Uses SUCTION CUPS (PETECHIOMETER)

15-20 mmHg

ELLIOT METHOD - Maintain pressure of ____ for 1 minute

Negative

Reporting for ELLIOT METHOD: 0-10 fresh petechiae

Positive

Reporting for ELLIOT METHOD: >10 fresh petechiae

• Thrombocytopenia - Idiopathic & Drug-induced & Immune-Induced

• Glanzmann thrombasthenia • Scurvy - Normal Platelet Count o Vitamin C deficiency causes vascular abnormality = positive result

• WOMEN

o positive shortly before their menstruation and 3 days into their cycle

o WOMEN >40 yrs old - not indicative of platelet disorder = due to decreased estrogen levels

Clinical significance for CFT

CLOT RETRACTION

Process by which serum is expressed from the clot

CLOT RETRACTION

In vitro reaction

Clot retraction

Happens when blood coagulation is complete

4 hours

Complete retraction occurs in how many hours at 37 degrees celsius

24 hours

Complete retraction occurs in how many hours at room temp

-Normal number of contractile platelets

-calcium

-ATP

-Normal concentration of fibrinogen

NORMAL CLOT RETRACTION REQUIREMENTS

Directly proportional

DEGREE OF CLOT RETRACTION: Number of platelets

Inversely proportional

DEGREE OF CLOT RETRACTION: Hematocrit & fibrinogen levels

Anemic states

DEGREE OF CLOT RETRACTION: Increased clot retraction Need to correct with patient's Hct

SINGLE TUBE METHOD

STEFANINI METHOD

SINGLE TUBE METHOD (STEFANINI METHOD)

QUALITATIVE METHOD; Measures clot retraction time

Normal clot

SINGLE TUBE METHOD (STEFANINI METHOD) RESULT: 2-4 hours

Poor clot

SINGLE TUBE METHOD (STEFANINI METHOD) RESULT: After 4 hours

None

SINGLE TUBE METHOD (STEFANINI METHOD) RESULT: No retraction occurs after 24 hours

MACFARLANE SERUM METHOD

QUANTITATIVE METHOD; Measures the degree of clot retraction

44-67%

MACFARLANE SERUM METHOD NORMAL VALUE _____

GP IIb/IIIa complex deficiency

Glanzmann thrombasthenia

Thrombocytopenia

Low platelet count -> low contractile platelets -> poor clot retraction

Hypofibrinogenemia/Dysfibrinogenemia

Low fibrinogen -> low fibrin -> small clot -> poor clot retraction = increase RBC fallout

Paraproteinemia (multiple myeloma, macroglobulinemia)

Presence of proteins - will interfere with fibrin formation -> poor clot retraction

Disseminated Intravascular Coagulation

Small clot -> poor clot retraction -> increase RBC fallout

High Hematocrit Level

Hematocrit & Clot retraction - inversely proportional increase hematocrit = decrease serum produced = poor clot retraction

corrected CR(%) = CR(%) x 100/100-Hct

Anemic states - corrected with