Hematology Lab Quiz Flashcards Preview

Med Lab Tech Fall 2016 > Hematology Lab Quiz > Flashcards

Flashcards in Hematology Lab Quiz Deck (50):
1

What is one of the most complex areas of diagnostic laboratory testing?

Hemostasis

2

What are the 3 steps for forming a clot?

1. constrict the blood vessel in the region of the hole

2. form a platelet plug

3. seal that plug with fibrin

3

What is platelet poor plasma?

contains less than 10 x 109 platelets/L

4

What are some specimen factors affecting coagulation testing?

  • collection system
    • order of draw
  • anticoagulant
  • phlebotomy technician
  • centrifugation
  • delays in handling
  • storage conditions

5

What are some instrument factors affecting coagulation testing?

  • temperature
  • light sensor
  • detector
  • timer
  • disposables
  • reagent delivery

6

What are some reagent and control factors affecting coagulation testing?

 

  • shipping conditions
  • storage conditions
  • reconstitution
  • contamination
  • deterioration
  • lot changes

7

What must be analyzed with each assay performed within the lab?

Internal Quality Control (IQC)

8

What is the purpose of internal quality control?

To assess ongoing assay performance to ensure assays are:

  • performing according to specifications
  • results are accurate and reliable
  • ensure reproducibility of testing

9

Definition:

Peer group assessment process that allows a lab to assess individual analytes against those of other labs using either the same or different reagents or instrumentation

External Quality Assurance

10

What anticoagulant is used for routine coagulation testing?

Sodium citrate

11

True or False:

If sodium citrate anticoagulant is unavailable, you may use EDTA, heparin, or oxalate.

False, these anticoagulants are unacceptable

12

What is the ratio of blood to anticoagulant?

9:1

13

A disproportion of blood to anticoagulant is seen in a patient with what disorder?

Polycythemia

14

What is the calculation used to calculate the amount of sodium citrate that should be used?

 

  • X= (100-Hct)Vol/(595-Hct)
    • X = volume of sodium citrate required for unit volume of blood
    • Hct = hematocrit
    • Vol = blood draw volume required in the blood collection tube

15

Most clot based coagulation activity procedures are performed on what type of specimen?

Plasma

16

The addition of what to plasma is required in order to perform coagulation activity testing?

The addition of CALCIUM is required in order to perform tests

17

What pathway include factors X, V, II, and I?

Common pathway

18

Which pathway includes factor VII?

Extrinsic pathway

19

Which pathway include factors XII, XI, IX, and VIIIa?

Intrinsic pathway

20

What are some advantages of enzyme specific synthetic substrates over the traditional clot formation?

  • can be performed rapidly
  • sensitive
  • allow for a greater degree of standarization
  • require smaller sample volumes
  • well suited for automation

21

If unable to perform testing within 4 hours what should be done?

Freeze plasma at -70C

22

Immediately before testing plasma, how should you thaw it when frozen?

Rapidly thaw in a 37C water bath to prevent formation of cryoprecipitate

23

What are the 4 methods of endpoint detection?

  • Mechanical
  • Photo-optical
  • Chromogenic
  • Immunogenic

24

A fibrometer is what type of endpoint detection method?

Mechanical

25

What type of endpoint method is the following:

when a light souce of a specified wavelength is passed through a test solution (plasma), a certain amount of light is detected by a photodetector or photocell located on the other side of the solution

Photo-optical endpoint detection

26

This endpoint detection method is the most commonly utilized in coagulation instruments

Photo-optical endpoint detection

27

What is another name for photo-optical endpoint detection?

Turbidometric methodology

28

This endpoint detection method is also known as amidolytic methodology

Chromogenic Endpoint Detection

29

The color-producing substance used in chromogenic endpoint detection is known as what?

Chromophore

30

This endpoint detection method is based on antigen-antibody reactions

Immunogenic endpoint detection

31

What bings von Willebrand Factor (vWF)?

Glycoprotein Ib

32

What binds fibrinogen?

Glycoprotein IIb-IIIa

33

These granules inside platelets are also known as specific granules and contain fibrinogen, von Willebrand factor, platelet-derived growth factor, and P-selectin

alpha granules

34

These granules are known as dense granules and contain serotonin, ATP, ADP, and calcium (which is necessary for the vitamin K dependent coagulation factors)

delta granules

35

What type of proteins help the platelet change shape during adhesion?

Contractile proteins (like actin)

36

What are the 3 steps of platelet plug formation?

1. adhesion

2. activation

3. aggregation

37

Definition:

measured as a screening procedure used to detect both congenital and acquired disorders of platelet function and von Willebrand disease..

Bleeding Time

38

Whare are the 4 procedures in use for determining bleeding time?

  • Duke method
  • Ivy method
  • Mielke method
  • Surgicutte or Simplate method

39

This bleeding time method punctures the ear lobe

Duke method

40

This bleeding time method requires a blood pressure cuff to maintain constant pressure within the capillaries to help standardize the procedure. The forearm is the site used and a lancet is used to make the incision. The greatest source of variation is in performing a standardized puncture.

Ivy method

41

This bleeding time method is a modification of the Ivy method. A disposable blade (scalpel) is used.

Mielke method

42

This bleeding time method is the preferred method. The device used has a trigger and spring method for the blade to make a precise 1.0 mm depth cut with a width of 5.0 mm.

 

Surgicutte/Simplate method

43

During the bleeding time procedure, the filter paper is slid into the droplet of blood how often until bleeding ceases?

Every 30 seconds

44

During the bleeding time procedure, the sphygmomanometer is kept at what measurement?

40 mmHg

45

What is the normal range for bleeding time?

2.5-9.5 minutes

46

What may cause a porlonged bleeding time?

  • The use of aspirin, aspirin-containing drugs, non-steroidal anti-inflammatory drugs, and antihistamines
  • If the alcohol used to clean the puncture site isn't fully dried
  • If the technician allows the filter paper to touch the wound, the platelet may dislodge

47

Obtaining an accurate bleeding time may not be possible in what type of patients?

Older patients because bleeding may only occut subcutaneously

48

True or False:

Thrombocytopenia with a platelet count less than 50,000/uL may cause a shortened bleeding time

False- it would cause a prolonged bleeding time because there are less platelets to form the plug

49

What are some inherited platelet dysfunctions that would cause prolonged bleeding times?

Bernard Soulier syndrome

or

Glanzmann's thromboasthenia

or

Storage pool disease

50

True or False:

Von Willebrand disease causes a shortened bleeding time

False

Von Willebrand disease causes a prolonged bleeding time