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Hematology > [LAB] Hemostasis Lab Testing (Part 1) > Flashcards

[LAB] Hemostasis Lab Testing (Part 1) Flashcards

1
Q

What type of plasma is used for the hemostasis procedure whereby platelet count is less than 10,000/ μL prepared from whole venous blood collected by venipuncture?

A

Platelet-poor plasma (PPP)

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2
Q

What type of plasma is used for light transmittance platelet aggregometry whereby platelet count is approximately 200,000/μL?

A

Platelet-rich plasma (PRP)

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3
Q

Hemostasis testing begins in ____ and ____.

A

bleeding and thrombosis risk assessment

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4
Q

Patients under drug therapies and dietary supplements are instructed to discontinue nonprescription drugs ____ prior to blood collection.

A

at least a week

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5
Q

If the patient has multiple bruises, mention a tendency to bleed, or possesses a high-risk BAT score, the phlebotomist should extend the time for observing the venipuncture site from the usual 1 minute to _____ and should apply a pressure bandage before dismissing the patient.

A

5 minutes

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6
Q

Patients are advised to avoid caffeine and exercise for ____ before collection.

A

2 hours

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7
Q

Patients are advised to avoid smoking for ____ before collection.

A

30 minutes

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8
Q

What is the usual gauge size for hemostasis collection on adults with good veins?

A

20-21 gauge

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9
Q

What gauge size will you use in the case of small, scarred, or fragile veins?

A

23-gauge

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10
Q

When transferring blood from a syringe to tube, what is the preferred needle gauge?

A

19-gauge

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11
Q

What is the top color of the collection tube used for the hemostasis specimen?

A

blue-top

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12
Q

What is the anticoagulant used for most hemostasis testing?

A

buffered 3.2% sodium citrate

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13
Q

What is the mechanism of a sodium citrate anticoagulant?

A

binds calcium ions to prevent coagulation

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14
Q

What is the purpose of the buffer?

A

stabilize specimen pH

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15
Q

What is the ratio of anticoagulant and blood?

A

9:1 (9 parts whole blood to 1 part anticoagulant)

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16
Q

What is the usual concentration of the anticoagulant and blood collected in evacuated plastic collection tubes?

A

0.3 mL of anticoagulant
2.7 mL of whole blood

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17
Q

What is the final citrate concentration following the ratio?

A

10.5-10.9 mM

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18
Q

The formula for computing the amount of anticoagulant.

A

C = (1.85 X 10^–3) (100-HCT) V

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19
Q

What is the mechanism of EDTA?

A

irreversibly chelates calcium ions

20
Q

True or False.

EDTA is one of the anticoagulants used for hemostasis testing.

A

False.

(Laboratory practitioners do not use EDTA for clot-based coagulation testing because EDTA irreversibly chelates calcium ions)

21
Q

Identify the anticoagulant.

  • produce accurate platelet counts in cases of platelet satellitosis (satellitism) as a substitute for specimens collected in EDTA.
A

Heparin (green)

22
Q

Identify the anticoagulant.

  • suppress in vitro platelet or coagulation activation for specialty assays
A

Citrate theophylline adenosine dipyridamole (CTAD, blue closure)

23
Q

True or False.

If a series of evacuated tubes is to be filled from a single venipuncture site, the hemostasis specimen must be collected before a nonadditive tube.

A

False.

(hemostasis specimen must be collected first or immediately after a nonadditive tube)

24
Q

What is the minimum required volume of blood during collection?

A

90%

25
Q

True or False.

The smaller the collection tube, the narrower the tolerance for short draws.

A

True

26
Q

How many times should a phlebotomist invert the collection tube?

A

at least 3 times

27
Q

What refers to excessive specimen agitation?

A

cocktail shaking

28
Q

Before specimen collection from the vascular access device, the line must be flushed with _____.

A

5mL of Saline

29
Q

How much blood is discarded first during collection on VAD?

A

5mL

30
Q

True or False.

The blood collector may flush with heparin.

A

False.

The blood collector must not flush with heparin.

31
Q

Where is the usual site of collection for capillary punctures?

A

third (middle) finger or fourth (ring) finger

32
Q

What is the function of collection tube seals?

A

minimizes CO2 diffusion

33
Q

Sodium citrate-anticoagulated whole blood specimens are placed in a rack and allowed to stand in a _____.

A

vertical position

34
Q

What is the temperature range to maintain the specimens?

A

15-25℃

35
Q

What temperature activates factor VII, activates platelets, and precipitates large VWF multimers?

A

1-6℃

36
Q

PT specimens at 15° C to 25° C are tested within ____ of the time of collection.

A

24 hours

37
Q

PTT specimens at 15° C to 25° C are tested within ____ of the time of collection.

A

4 hours

38
Q

If a patient is receiving unfractionated heparin (UFH) therapy, PTT specimens must be centrifuged within ____ of the time of collection to avoid depletion of the heparin.

A

1 hour

39
Q

Specimens may be stored at –20° C for up to ___.

A

2 weeks

40
Q

Specimens may be stored at –70° C for up to ___.

A

6 months or so

41
Q

What are the methods used for testing whole-blood specimens?

A
  • lumiaggregometry
  • thromboelastography (TEG)
  • thromboelastometry (ROTEM)
42
Q

What is the instrument used for testing PRP?

A

Light-transmittance (optical) platelet aggregometer

43
Q

What is the method used for testing PPP with a platelet count of less than 10,000/μL?

A

Clot-based plasma coagulation tests

44
Q

What is the method used for testing PPP with a platelet count of less than 5,000/μL?

A

Double-spin approach

45
Q

Identify the settings for the centrifuge.

  • Light-transmittance (optical) platelet aggregometer for PRP
A

50 X g RCF for 30 minutes

46
Q

Identify the settings for the centrifuge.

  • Clot-based plasma coagulation tests for PPP
A

1500 X g RCF for 15 minutes

47
Q

Identify the settings for the centrifuge.

  • HemoCue StatSpin for PPP
A

4400 X g RCF for 3 minutes

Hematology (8 decks)

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