MIDTERM: Clot Retraction Time (lab) Flashcards

1
Q

Tube that is graduated to 5ml and is used in CRV, Mc Farlene method

A

Conical centrifuge tube

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2
Q

Tightening of the fibrin clot

A

Clot retraction

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3
Q

Terms applied to shrinkage of the blood clot

A

Syneresis

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4
Q

The separation of the blood clot from the wall of the test tube is normally observed after _____? And is complete after?

A

1 hour and 2 hours, respectively

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5
Q

The clot is approximately how many percent of the original blood volume?

A

50%

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6
Q

The reduction of the coagulum in mass and fluid serum being expressed from the clot is due to what?

A

Action of platelet on the fibrin network

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7
Q

State the principle of clot retraction

A

Clot retraction is directly proportional to platelets and inversely proportional to the hematocrit and fibrinogen levels

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8
Q

TRUE OR FALSE:
When fibrinolysis is very active, the fibrin may dissolved longer as it is formed and clot retraction will not be impaired.

A

FALSE. Fibrin dissolves almost as quickly as it is formed when fibrinolysis is very active, resulting to impaired clot retraction

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9
Q

In clot retraction time, how many ml of venous blood do you place in a test tube?

A

5mL

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10
Q

Ideal measurement of a coiled wire In clot retraction test.

A

1 mm thick with a 3cm diameter coil

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11
Q

In clot retraction time, how long do you incubate the venous blood?

A

37 degrees Celsius for 1 hour

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12
Q

In clot retraction time, how long do you allow the attached clot to drain?

A

2 minutes

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13
Q

Describe the characteristics of a normal clot

A

Firm, difficult to break up with blunt instruments and difficult to flatten out

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14
Q

In clot retraction time, what do you read in the last step?

A

Volume of the fluid remaining in the tube

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15
Q

Normal value in clot retraction time

A

44-67%

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16
Q

Describe the characteristics of a defective clot

A

Soft, pliable, easily crushed

17
Q

In this condition, a coagulum is formed in the normal time but it does not retract.

A

Thrombocytopenic purpura

18
Q

The coagulum forms very slowly, but once the clot is formed, it retracts normally

A

Hemophilia

19
Q

In which cases does the serum volume is abnormally high?

A

Anemia

20
Q

Corrected CR% is used when?

A

Serum volume is abnormally high like in cases of anemia

21
Q

Corrected CR% formula

A

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

22
Q

Clot retraction formula

A

Clot retraction (CR%) = volume or height of serum (S) / volume or height of whole blood (T) x 100