EXERCISE 8: BLEEDING TIME AND COAGULATION TESTING
Skills: 23 points
OBJECTIVES:
1. Define the following terms: hemostasis, coagulopathy, reproducibility, sensitivity
2. List and briefly describe the five steps of coagulation
3. State three reasons coagulation tests are ordered.
4. Name the commonly ordered coagulation test often used to monitor oral anticoagulant therapy
5. List the proper blood to anticoagulant ratio used for coagulation testing, and why it is important.
6. List two unique collection techniques when drawing blood for coagulation tests.
7. List three factors on which the duration of the bleeding time is dependent.
8. Identify the purpose of the bleeding time test.
9. Compare and contrast four types of bleeding time methods.
10. Describe the proper patient preparation for the bleeding time test.
11. Explain the importance of asking the patient about blood thinners and aspirin
12. State the reference values for the bleeding time test.
13. Identify at least four sources of error for the bleeding time test and indicate how each would affect the test
results.
14. Describe the course of action which should be taken when the bleeding time exceeds 15 minutes.
15. Describe and perform the bleeding time procedure as outlined in this lab.
Coagulation Overview
Hemostasis involves a complex series of processes by which the body stops the loss or leakage of blood if an injury
should occur while keeping the circulating blood in a fluid state. Coagulation is the part of hemostasis that deals
with stopping the leakage of blood from a wound or blood vessel. Coagulopathy is also called “clotting disorder”
or “bleeding disorder” and occurs when a patient has a problem in the hemostasis process. Examples include
thrombocytopenia, which is a decreased number of platelets; qualitative platelet defects, which occur when the
platelets do not function properly; vascular abnormalities and von Willebrand's disease.
After an injury, the coagulation process proceeds in five steps:
1. Vasoconstriction – the damaged capillaries and other vessels rapidly constrict decreasing the blood flow to
the injured tissues.
2. Platelet plug formation – bleeding is slowed by the platelets sticking together at the site of the injury
3. Fibrin clot formation – a complex cascade of reactions involving the clotting factors, calcium and other
proteins to form a fibrin mesh and create the hemostatic plug.
4. Clot Retraction – bleeding has stopped and the clot contracts to bring the edges of the injury together
5. Fibrinolysis – the injured tissues are healed and the body breaks down and dissolves the clot, breaking it into
small fragments called fibrin degradation products (FDP)
Coagulation Tests
Three primary reasons for ordering coagulation tests are:
1. To diagnosis coagulopathies.
2. To monitor patients on anticoagulant therapy.
3. To evaluate a patient’s blood clotting status prior to surgery.
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
The most frequently ordered coagulation test for diagnosis of coagulopathies are the Prothrombin Time (PT), the
Partial Thromboplastin Time (aPTT), the quantitative Fibrinogen and the Thrombin Time (TT). Other tests used
for diagnosis and monitoring of the coagulation system include the Activated Clotting Time (ACT), Fibrin
Degradation Products (FDP), D-dimer, and Cryofibrinogen, as well as specific factor assays and coagulation
mixing studies. Platelet counts are also utilized and are performed in Hematology.
Patients with an increased risk of forming harmful blood clots are often prescribed an oral anticoagulant
medication, which patients often call “blood thinners”. Examples of these medications include sodium heparin,
Coumadin (warfarin) and Lovenox (enoxaparin). These patients are closely monitored as the metabolism of the
drugs varies with each individual. The Prothrombin Time (PT) is the most commonly ordered test to monitor
patients on blood thinners.
Collection of Specimens for Coagulation Testing
Proper filling of the sodium citrate tube is important in order to achieve the proper 9:1 ratio of blood to
anticoagulant. It is essential to completely fill the tube as failure to do so will cause rejection of the sample as
improperly filled tubes can lead to incorrect results.
IMPORTANT: When using a winged blood collection set for Venipuncture and a coagulation tube is the first
tube to be drawn, a discard tube should be drawn first. The discard tube must be used to clear the air from the
tubing (dead space) to assure maintenance of the proper anticoagulant to blood ratio. The discard tube need not be
completely filled and can be an additional blue top tube or a special non-additive discard tube designed for this
purpose.
Another coagulation test which requires unique collection technique is the Cryofibrinogen. The sample must be
collected into a pre-warmed, light blue tube maintained at 37 degrees until processed. Check the protocol of the
clinical facility for their requirements.
Overview of the Bleeding Time Test
The bleeding time test is a useful tool for testing platelet plug formation in the capillaries. It is generally used in
conjunction with other coagulation tests. Its primary use is as a pre-surgical assessment of a patient’s likelihood
of bleeding excessively from a surgical wound. Patients with family history of bleeding, those with suspected
congenital or acquired platelet defects, vascular disorders, or vonWillebrand’s disease may also benefit from this
test. In recent years, requests for bleeding time testing have greatly declined in favor of better, more specific
coagulation tests.
The test is performed by applying a blood pressure cuff to the upper arm of the patient, inflating it to 40 mmHg,
making a minor incision of a standardized depth and length in the forearm and recording the length of time
required for bleeding to cease. The duration of the bleeding time depends upon the:
1. quantity of platelets
2. quality of platelets
3. ability of the blood vessel wall to constrict.
Bleeding Time Methods
Duke Method
In 1910, Duke originally described a method which used a lancet to puncture the earlobe. This test was difficult to
standardize, did not allow space for repeat testing and often caused undue apprehension in the patient.
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
Ivy Method
In 1941, Ivy et al made the first attempts to standardize the procedure. The test is performed on the inner side of
patient’s forearm with a blood pressure cuff applied to the upper arm of the patient and inflated to 40 mm Hg.
The blood pressure cuff is used to control capillary tone and improves both sensitivity and reproducibility.


Sensitivity refers to the ability of a test to detect borderline abnormalities.
Reproducibility of a test is when two persons perform the same procedure under identical circumstances and
obtain identical test results.
The test results continued to be difficult to reproduce due to difficulty in performing a standardized depth and
length of puncture.
Mielke Method
In 1969, Mielke introduced a modification of the Ivy Method which further improved standardization of the test.
It kept the use of the blood pressure cuff at 40 mm Hg and the use of the forearm as the test site. A scalpel and
polystyrene template for holding the scalpel were used to standardize the length and depth of the incision.
The advantages of this method included:
1. A surgical incision that more closely approximates the patient’s hemostatic response to surgery.
2. Large surface area of the template minimized skin displacement.
3. The depth of the incision could be controlled.
Disadvantages of this method include:
1. The unconcealed scalpel caused patient apprehension.
2. The scalpel and template required sterilization after each use.
3. Small scars might form.
Commercial Bleeding Time Devices
The most recent modification of the Ivy bleeding time occurred in 1978 with the production of a commercially
produced bleeding time device. This was marketed under various names, including Simplate, Surgicutt and Triplett.
These devices make a standardized incision of a specific depth and length. The instrument is a spring-activated
surgical steel blade housed in a self contained plastic unit from which the blade protracts and retracts automatically
which improves the safety of the procedure. Patients must be informed of the potential of scarring prior to
performing the procedure.
Advantages of this method include:
1. Instrument is a sterile, disposable, self-contained device which minimizes patient anxiety.
2. Makes standardized surgical incision of specific depth and length.
3. Improves safety for both patient and phlebotomist.
A disadvantage of this method is that small scars may form.
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
Preparation of the Patient
After properly greeting and identifying the patient and yourself, the following items must be discussed with the
patient:
1. Explanation of procedure - Explain that a "bleeding time" test has been ordered by their doctor and is a
test to see how long it will take for them to stop bleeding after a small incision is made in their forearm.
Inform them that the test may take 15 to 30 minutes to complete.
2. Discomfort- there may be some minor discomfort from the incision and the blood pressure cuff.
3. Scar Formation –patients should be informed that they may receive slight scarring at the incision site.
4. Medication History – Some medications will cause an abnormally increased bleeding time which may
require the test to be rescheduled until 7-10 days after their last dose. The patient’s physician should be
consulted. Ask the patient if they have taken any of the following during the past 7-10 days.
a. Aspirin or aspirin containing medications including over the counter medications.
b. “Blood thinners” such as heparin or Coumadin
After explaining the basic steps of the procedure ask the patient if they have any questions. The phlebotomist
may answer ONLY those questions concerning the procedure itself. Any questions a patient may have about the
significance of the test and the test results must be referred to the physician who ordered the test as only the
patient's physician can interpret test results within the context of the individual patient's condition.
Important: If bleeding continues for more than 15 minutes, the procedure should be discontinued, and pressure
applied to the wound site. The bleeding time test should be repeated on the patient’s other arm. If the second test
produces the same results, the test is reported as greater than 15 minutes.
Quality Assurance
Quality control is accomplished through the standardization of the procedure. The wound should be a standard
length and depth, the blood pressure cuff maintained at a constant pressure of 40 mmHg, using a calibrated
stopwatch or other timing device, and care is taken to avoid disrupting the forming clot.
Sources of Error
1. Failure to ask patient about medication history. The effects of aspirin or an “blood thinner” will cause the
bleeding time to be prolonged.
2. Improperly performed puncture - a puncture that is too shallow, too deep, or in an inappropriate location will
adversely affect test results.
3. Alcohol not completely dried before making the puncture. If residual alcohol is on a puncture site, the
bleeding time will be erroneously prolonged.
4. Timing - If the phlebotomist does not initiate timing of the procedure simultaneously with the puncture, the
results will be adversely affected.
5. Improper application of filter paper to blood drop. If the phlebotomist allows the filter paper to touch the
wound, the platelet clot may be dislodged, causing falsely elevated results.
6. Calibration - If the stopwatch has not been appropriately calibrated, it may keep incorrect time. Stopwatches
should be calibrated on a regular basis as a part of the quality assurance program.
Reference Values
1.0 - 9.0 minutes
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
EXERCISE 8: MODIFIED IVY BLEEDING TIME
Materials:
1.
2.
3.
4.
5.
6.
Blood pressure cuff
Sterile, disposable blood lancet
Stopwatch
Circular filter paper
Alcohol pads
Gloves
7. Bandage
Procedure:
1. Greet and properly identify the patient and yourself.
2. Sanitize hands and put on gloves.
3. Select, prepare and organize necessary equipment.
4. Explain the procedure to the patient including overview, discomfort, time, and scar formation.
5. Ask about aspirin, aspirin containing compounds and “blood thinners” taken within last 7-10 days.
6. Select a site on the patient's forearm approximately three fingers widths below the bend in the elbow that
is free of visible veins or capillaries.
7. Place a blood pressure cuff on the patient's arm above the elbow. Do not inflate the cuff until 30-60
seconds before your perform the puncture.
8. Cleanse the outer surface of the patient's forearm by moving the alcohol pad firmly in concentric circles
from the incision site outward; allow to air dry.
9. Open and prepare the bleeding time device according to manufacturer’s directions. If needed, remove
safety clip being careful not to touch or contaminate the blade-slot surface.
10. Turn the knob on the bulb of the sphygmomanometer to close. Squeeze the bulb to inflate the blood
pressure cuff to 40 mm Hg and tighten knob to maintain the pressure.
11. Place the device on the desired incision site, parallel to the anticubital crease, making sure it is well
seated, but NOT pressing into the skin.
12. Depress the “trigger” on the bleeding time device AND simultaneously start the stopwatch.
13. After 30 seconds have passed, touch the filter paper to the bottom of the drop of blood to wick the blood
into the filter paper. It is extremely important that the filter paper does NOT touch the wound on the
arm.
14. Every 30 seconds, rotate the filter paper slightly and wick the blood onto the next section of filter paper,
15. Stop the stopwatch once the bleeding has completely ceased and it no longer wicks onto the filter paper
OR 15 minutes has elapsed.
16. Release the blood pressure cuff by turning the knob next to the bulb in the opposite direction used to
inflate the cuff. Remove the blood pressure cuff.
17. After ensuring that the bleeding has stopped, carefully bandage the site. If the bleeding time is 15
minutes or greater repeat on opposite arm.
18. Count the number of blood spots on the filter paper and record the bleeding time to the nearest 30
seconds. Each blood spot equals 30 seconds. (Example: if there were 5 blood spots the time would be
recorded as 2 minutes 30 seconds)
19. Appropriately discard all used materials and wash hands.
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
Phlebotomy Technician Program
Bleeding Time Test Skills Assessment Form
Phlebotomist (PRINT) (0.5 point): __________________________
Date: _________ Points:
/25
Partner or Instructor (PRINT) (0.5 point): ___________________________________________________
Instructions: The activity is to be started by the phlebotomist’s introduction. Evaluator is to place a “” in the
appropriate column. ALL critical areas (shaded boxes) must be performed within the allotted time to pass
skills test.
TIME LIMIT: 30 minutes
Start Time:
End Time:
Total Time:
1 point
Skills
Performed
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
Introduces self as student and states mission. *Start Time*
Properly identifies patient.
Washes or sanitizes hands. Puts on gloves.
Explains procedure to the patient.
Questions patient about drugs and medications (including aspirin or aspirin products) they
have taken during past 7-10 days.
Selects, prepares and organizes equipment including lancet device.
Selects an appropriate site for the bleeding time test.
Apply blood pressure cuff to arm DO NOT inflate.
Cleanses the incision site using appropriate technique.
Inflates the blood pressure cuff at 40 mm Hg.
Make the incision within 30-60 seconds of inflating the blood pressure cuff.
Starts stopwatch or timing device as soon as incision is made.
Appropriately wicks flow of blood onto filter paper from incision every 30 seconds.
Observes for the cessation of bleeding and stops timing when bleeding has ceased or 15
minutes has elapsed.
Releases gauge on blood pressure cuff, removes blood pressure cuff.
Carefully cleanses around the incision site and applies an appropriate bandage.
Records time at the bottom of this form USING APPROPRIATE UNITS. Label filter
paper and submit to instructor.
Dispose of lancet in sharps container.
Dispose of other used materials appropriately and removes all equipment.
Removes gloves, washes or sanitizes hands.
Leaves patient courteously.
22. Result of Bleeding Time: ______________________________
23. Bleeding time is (circle one): NORMAL ABNORMAL
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
Not
Performed
EXERCISE 8: BLEEDING TIME & COAGULATION TESTING STUDY QUESTIONS
Name: ____________________________
Date: ______________ Points:
/31
1. Define the following terms (4 points):
a. Hemostasis
b. Coagulopathy
c. Sensitivity
d. Reproducibility
2.
Identify the three reasons for which coagulation tests are ordered. (3 points)
a.
b.
c.
3. State the most commonly ordered coagulation test used to monitor patients on blood thinners. (1 point)
4. State the proper blood to anticoagulant ratio for coagulation test collected in the light blue stoppered tube.
(1 point)
5. What precaution should be taken when collecting a coagulation test using a winged infusion set? (1 point)
6. The duration of the bleeding time is dependent on three factors. List them. (1.5 points)
a.
b.
c.
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
7.
Briefly describe the Duke bleeding time method and state two drawbacks of this procedure (1.5 points).
a.
b.
c.
8. List two ways the Ivy bleeding time method differs from the Duke bleeding time method. (2 points)
a.
b.
9. What is the purpose of using the blood pressure cuff during the bleeding time procedure? (1.5 points)
a.
b.
c.
10. Briefly describe how the Mielke bleeding time method differs from the Ivy method (1 point).
11. List two advantages the Mielke method has over the Ivy method. (2 points)
a.
b.
12. List 3 advantages of using a commercial device for the bleeding time procedure. (3 points total)
a.
b.
c.
13. List four items which should be discussed with the patient during the interview process for the bleeding time.
(2 points)
a.
b.
c.
d.
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|
14. List two medications which may affect the bleeding time and how the bleeding time will be affected. (1.5
points)
a.
b.
c.
15. What is the correct response to give to patients who inquire about the significance of the test results? (1 point)
16. State the course of action which should be taken when the bleeding time exceeds 15 minutes. ( 1 point)
17. List four sources of error in the bleeding time procedure. (2 points)
a.
b.
c.
d.
18. What are the reference values for the bleeding time test? (1 point)
points).
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Exercise 8:Bleeding Time and Coagulation Testing (Rev 9/13/13)|