Platelets: Lab Tests/Disorders

Question 1

If PLTs is <50 counted on each side, repeat procedure and dilute blood to ___________

Answer 1

1:20

dilute to 1:200 if >500 PLTs counted

Question 2

Unopette system’s buffer to maintain pH

Answer 2

Sorensen’s phosphate buffer

Question 3

Antibacterial agent of Unopette sustem

Answer 3

Thimerosal

Question 4

Which manual platelet count (indirect method) uses Reese ecker fluid

Answer 4

Dameshek (Indirect - Wet Method)

Question 5

Best indirect manual platelet count method

Answer 5

Olef method

same principle w/ Fonio but blood to diluting fluid ratio is 1:5 instead of 1:3 (Fonio)

Question 6

Normal blood smear demonstrates ______________ (#) plts/field

Answer 6

8-20

Question 7

Formula for platelet estimate per uL of blood

Answer 7

Platelet estimate = (average # of PLTs per field) x (20,000)

Question 8

Normal plt estimate value

Answer 8

200,000 - 400,000/uL

Question 9

Gold standard to determine platelet function

Answer 9

Platelet aggregation test

Question 10

Agonists for plt aggregation test

Answer 10

EACTR2A

Epinephrine, ADP, Collagen, Thrombin, Ristocetin, Arachidonic Acid

Question 11

Most commonly used agonist for plt aggregation test

Answer 11

ADP

produces biphasic aggregation

Question 12

Normal clot retraction requires ________________

Answer 12

Normal # of functioning plts
Calcium
ATP
Fibrinogen

Question 13

________ or _________ is responsible for clot retraction

Answer 13

Actomyosin
Thrombostenin

Question 14

Prolonged bleeding time in Px w/ plt count of >100x10^9/L indicates that platelets are ____________ or a defect of _____________

Answer 14

Impaired in function
Subendothelial factor

Question 15

Lab tests for primary hemostsis

Answer 15

Platelet count
Platelet aggregation test
Platelet adhesion test
Clot retraction time
Capillary fragility test
Glass bead retention test
Bleeding time

Question 16

PT determine the ____ and _____ payhway factor deficient

Answer 16

Extrinsic
Common

Question 17

Specimen used for PT

Answer 17

Platelet poor plasma

Question 18

Test used to monitor for Warfarin / Coumadin therapy

Answer 18

Prothrombin time

Question 19

Serves as a sensitive early marker for mild liver disease that can detect factor VII deficiency and Vitamin K deficiency

Answer 19

Prothrombin time

Question 20

APTT is ysed for determination if ________ and _______ pathway factor deficient

Answer 20

Intrinsic
Common

Question 21

standard method for monitoring unfractionated heparin therapy

Answer 21

APTT

Question 22

Test for fibrinogen deficiency

Answer 22

Thrombin time / Thrombin clotting time

Reptilase time also, test for fibrinogen deficiency and abnormality

Question 23

Test that uses a specimen diluted with Owren’s buffer

Answer 23

Clauss fibrinogen assay

(PPP diluted 1:10 with buffer)

Question 24

Determines the coagulation factor deficient in the common pathway

Answer 24

Stypven time / Russel viper venom time

Question 25

Duckert’s test is a screening test for factor ________ deficiency

Answer 25

XIII

Question 26

Test for INCREASED fibrinolysis

Answer 26

Whole blood clot lysis time

Question 27

Presence of _______________ indicates that a stable fibrin clot has been lysed

Answer 27

Crosslinked d-dimer

Question 28

Gold standard for measuring d-dimer

Answer 28

Classic microplate ELISA

Question 29

A qualitative agglutination immunoassay test for fibrin degradation product (FDP)

Answer 29

Thrombo-wellcotest (Thermo-fisher)

Question 30

Two physiologic human plasminogen activators

Answer 30

Tissue plasminogen activator - synthesized in vascular endothelial cells (VEC)
Urokinase - produced in the kidney and VEC

Question 31

TPA and urokinase is inhibited by…

Answer 31

PAI-1 (Plasminogen activator inhibitor-1)

Question 32

PAI-1 is produced by…

Answer 32

Vascular endothelial cells and hepatocytes

Question 33

Mechanism of inactivation of PAI-1

Answer 33

Covalent bonding

Question 34

PAI-1 assay specimen collection tube

Answer 34

Acidified citrate tube (Stabilyte)

(same w/ Tissue Plasminogen activator assay)