Hematology Lab Final Flashcards Preview

Med Lab Tech Fall 2016 > Hematology Lab Final > Flashcards

Flashcards in Hematology Lab Final Deck (94):
1

The purpose of ______ ________ is to detect a lab error that may result in a clinical error.

Quality control

2

___________________ identifies several major activities of importance to a laboratory quality program.

Clinical Laboratory Standards Institute (CLSI)

3

What are the three step for clotting?

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

2. Form a platelet plug

3. Seal the plug with fibrin

4

Specimen factors affecting coagulation testing (6)

  • Collection system
    • Order of draw
  • Anticoagulant
  • Phlebotomy technique
  • Centrifugation
  • Delays in handling
  • Storage conditions

5

Specimen factors affecting coagulation testing falls under:

A. analytical

B. Preanalytical

C. Preanalytical and analytical

C. Preanalytical and analytical

6

Instrument factors affecting coagulation testing include (6)

  • Temperature
  • Light sensor
  • Detector
  • Timer
  • Disposables
  • Reagent Delivery

7

Instrument factors affecting coagulation testing fall under:

A. analytical

B. Preanalytical and analytical

C. Preanalytical

A. analytical

8

Reagents and Control factors affecting coagulation testing include (6)

  • Shipping conditions
  • Storage conditions
  • Reconstitution
  • Contamination
  • Deterioration
  • Lot changes

9

Reagent and control factors affecting coagulation testing are a part of:

A. Analytical

B. Preanalytical

C. Preanalytical and Analytical

A. Analytical

10

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

11

What is External Quality Assurance?

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

12

What is the anticoagulant used in coagulation studies?

Sodium citrate

13

What is the ratio of blood to anticoagulant?

9:1

14

Clot based methodologies are usually performed at what temperature?

37C +/- 1

15

Freeze plasma at ______ is unable to perform testing within 4 hours

-70C

16

Freeze plasma at -70C if unable to perform testing within ____ hours

4 hours

17

A fibrometer is an example of:

a. Mechanical endpoint detection

b. Photo-optical endpoint detection

c. Chromogenic endpoint detection

d. Immunogenic endpoint detection

a. Mechanical endpoint detection

18

Diagnostica Stago STAanalyzers and the Trinity Biotech Destiny line are examples of:

a. Mechanical endpoint detection

b. Photo-optical endpoint detection

c. Chromogenic endpoint detection

d. Immunogenic endpoint detection

a. Mechanical endpoint detection

19

Photo-Optical endpoint detection is also known as what?

Turbidometric methodology

20

This is the most common method of detection utilized on coagulation instruments

Photo-Optical endpoint detection

21

What is also known as amidolytic methodology?

Chromogenic endpoint detection

22

This endpoint detection system is based on the attachment of pNA to a synthetic chromogenic substrate

Chromogenic endpoint detection

23

This type of endpoint detection is based on antibody-antigen reactions

Immunogenic endpoint detection

24

Definition:

the time taken for a standardized skin incision to stop bleeding

Bleeding Time (BT)

25

On vessel injury, platelets adhere to _________ exposed in the subendothelium with assistance from _____________ and form a homeostatic platelet plus.

collagen, von Willebrand Factor

26

What does bleeding time measure?

Platelet number and function

27

Which bleeding time method makes a standardized puncture of the ear lobe?

Duke Method

28

In this bleeding time method a blood pressure cuff is used to maintain constant pressure within the capillaries to help standardize the procedure, the forearm is the site of incision, and a sterile/disposable lancet is used.

Ivy Method

29

This bleeding time method uses a Bard-Parker or similar disposable blade

Mielke Method

30

This bleeding time method uses a spring activated device

Simplate/Surgicutte Method

31

What is the normal range for Bleeding Time?

2.5-9.5 minutes

32

What are some situiations that would cause a prolonged BT?

  • Thrombocytopenia
  • Inherited platelet dysfunction (Bernard-Soulier, Glanzmann's thrombasthenia, Storage Pool Disease)
  • After administration of aspirin
  • Antihistamines
  • Von Willebrand disease

33

What are some sources of error for BT?

  • Use of aspirin, aspirin-containing drugs, NSAIDs, and antihistamines
  • Alcohol
  • If the technician doesn't initiate timing of the procedure simultanerously with the puncture
  • If the technician allows the filter paper to touch the wound, causing the plug to become dislodged

34

What glycoprotein binds vWF?

GPIb

35

What glycoprotein binds fibrinogen?

GPIIb/IIIa

36

Alpha granules contain which of the following?

a. fibrinogen

b. vWF

c. platelet derived growth factor

d. P-selectin

e. all of the above

f. None of the above

e. all of the above

37

Dense granules contain which of the following?

a. serotonin

b. ATP

c. ADP

d. fibrinogen

e. A, B, and C only

e. A, B, and C only

 

Also- Calcium :)

38

These proteins found in platelets help the platelet change shape during adhesion.

Contractile proteins

39

When platelet stick to the subendothelium it is called _________

Adhesion

40

When platelets stick to each other and form a temporary plug it is known as _______________.

Aggregation

41

Definition:

The time required for the formation of a fibrin clot when plasma is added to a thromboplastin-calcium mixture

Prothrombin Time (PT)

42

Prothrombin time measure with coagulation pathway? (Include factor(s))

Extrinsic Pathway

Factors: I, II, V, VII, X

43

What factors are included in the prothrombinase complex?

FXa + FVa

44

What is the normal range of PT?

10 - 13 seconds

45

What can cause a prolonged PT?

  • Single or multiple factor deficiencies
  • presence of FDPs
  • Heparin
  • Polycythemia

46

What can cause a shortened PT?

  • When the plasma is stored for longer than 4 hours at 4C because of the cold activation of F VII

47

PT helps to monitor what drug(s)?

Warfarin and Coumadin

48

The therapeutic range of warfarin therapy is usually considered ro be a PT of __________

1.5 - 2 times the normal

49

Definition:

A screening test used to evaluate the intrinsic and common pathway of coagulation or more prescisely to measure all the plasma coagulation factors with the exception of F VII and F XIII

Activated Partial Prothrombin Time (APTT)

50

The APTT is used to screen for ________ of the intrinsic pathway such as _____________ and to monitor ________ therapy

inhibitors, lupus anticoagulant, heparin

51

What is considered a normal APTT result?

22.0 - 37.0 seconds

52

What may cause a prolonged aPTT?

  • An inherited or acquired deficiency of F I, II, V, VIII, IX, X, XII, Fletcher, and Fitzgerald
  • Warfarin therapy
  • Drug interactions
  • Liver disease
  • Circulating anticoagulants such as heparin, FDPs, and lupus inhibitor
  • Consumption of F I, II, C, and VIII in intravascular coagulation syndromes
  • Collection and technologic errors

53

Light Transmission Aggregometry uses what?

Citrated platelet rich plasma

54

What does Coumadin do?

It lengthens the time it takes for blood to clot

55

What are some medical conditions in which the formation of clots would be detrimental?

  • Atrial fibrillation
  • Deep vein thrombosis
  • Heart valve replacements

56

What does INR stand for?

International Normalized Ratio

57

What does ISI stand for?

International Sensitivity Index

58

What is the formula for INR?

INR = (Patient PT/PT reference plasma)ISI

OR

INR = (PT ratio)ISI

59

What are sources of thromboplastin?

  • Rabbit brain
  • Human brain
  • Recombinant

60

What is PIVKA?

Protein Induced Vitamin K Absence

When vitamin K is deficient, precursor proteins of F II, VII, IX, and Xbuild up and can be detected by PIVKA

61

What strengthens PIVKA?

  • Alcohol
  • Aspirin and similar products
  • Aminoglycosides
  • Ritalin
  • Tetracycline

62

What inhibits PIVKA?

  • Antacids
  • Antihistamines
  • Barbituates
  • Tegretol
  • Oral contraceptives
  • Vitamin K

63

Factors that affect the INR

  • Instrumentation (clot based assays vs light scatter)
  • Normal range determination
  • Assigned ISI values
  • Thromboplastin source
  • Sodium citrate concentration in collection tubes
  • Education

64

Normal range determinations should be done when?

  • Any change in instrumentation
  • Lot # changes/ New shipment of reagents
  • Change in collection procedure

65

Treatment for INR 2.0 - 3.0

  • Prophylaxis and treatment of venous thrombosis
  • treatment of PE
  • Prevention of systemic embolism
  • Tissue heart valves
  • Acute MI
  • Vavular heart disease
  • Atrial fibrillation

66

INR 3.0 - 4.5

  • Recurrent systemic embolism
  • Mechanical prosthetic valves
  • MI

67

The ______________ is similar to the Thrombin Time

Reptilase Time

68

True or False

In TT, thrombin hydrolyzes Fibrinopeptide A and B from fibrinogen

True

69

True or False:

In Reptilase Time, a snake venom enzyme hydrolyzes fibrinopeptide A and B from the intact fibrinogen molecule

False. Only fibrinopeptide A!

70

The advantage of the reptilase time is that it is not inhibited by __________

Heparin

71

There is only a minimal effect on the reptilase time by ______

FDPs

72

What is the normal range for reptilase time?

15 - 20 seconds

73

The reptilase time is infinitely prolonged is what cases?

  • FibrinogenOklahoma and FibrinogenOslow
  • Congenital dysfibrinogenemia
  • Congenital afibrinogenemia

74

Definition:

The time required for thrombin to convert fibrinogen to an insoluble fibrin clot.

Thrombin Time

75

What is the most comonly used source of thrombin in a TT?

Bovine thrombin

76

What is the normal value for Thrombin Time?

14 - 18 seconds

77

What are normal D-dimer levels in plasma?

Less than 250 ng/mL

78

What is one of the most important aspects of the D-dimer assay?

The negative predictive value when ruling out venous thromboembolism.

79

An elevated D-dimer level may be seen in clinical situations where active thrombosis is occurring such as _____, _____, and _____.

DIC, DVT, and PE

80

Plasmin proteolytically cleaves fibrinogen into fragment X and Y. These are known as what?

Early degradation products

81

Plasmin proteolytically cleaves fibrinogen into fragment D and E.

These are known as what?

Late degradation products

82

Measurement of FDPs provides an indirect assessment of _________

Fibrinolysis

83

Elevated levels of FDPs are associated with thrombic episodes such as what?

  • MI
  • PE
  • DVT
  • Liver disease
  • Active inflammation
  • Complications with pregnancy

84

FDPs assay is of value in the differential diagnosis of patients with specific types of _________ disease

Kidney

85

Formula for MCV

Normal Range

(HCT x 10)/RBC

Normal range: 82.0-98.0 fL

86

Formula for MCH (pg)

(HGB x 10)/RBC

 

87

Formula for MCHC

Normal range

(HGB x 100)/ HCT

Normal range: 32.0 - 36.0%

88

Factors in Adsorbed plasma (ADSP)

  • I
  • V
  • VIII
  • XI
  • XII
  • XIII
  • Fletcher
  • Fitzgerald

89

Factors in normal aged serum (NS)

  • VII
  • IX
  • X
  • XI
  • XII
  • Fletcher
  • Fitzgerald

90

Causes of a prolonged PT and normal aPTT

  • Inherited
    • Factor VII deficiency
  • Acquired
    • mild vitamin K deficiency
    • Liver disease
    • Warfarin administration
    • Lupus anticoagulant
    • Acquired inhibitor of FVII

91

Causes of normal PT and prolonged aPTT

  • Inherited
    • Deficiencies in factors VIII, IX, or XI
    • Deficiency of factor XII, prekallikrein, or HMWK
    • von Willebrand disease
  • Acquired
    • Heparin administration
    • Inhibitor of factors VIII, IX, XI, or XII
    • Acquired von Willebrand disease
    • Lupus anticoagulant

92

Causes of prolonged PT and aPTT

  • Inherited
    • Deficiency of prothrombin, fibrinogen, or factors V or X
    • Combined factor deficiencies
  • Acquired
    • Liver disease
    • DIC
    • Supratherapeutic doses of anticoagulants
    • Severe vitamin K deficiency
    • Combined heparin and warfarin administration
    • Direct thrombin inhibitor administration
    • Direct factor Xa inhibitor administration
    • Anticoagulant rodenticide poisoning
    • Inhibitor of prothrombin, fibrinogen, or factors V or X
      • Primarily amyloidosis-associated FX deficiency

93

What is the normal range for INR?

0.8 - 1.2

94

The antibody that inhibits factor VIII is most often?

Specific IgG antibody