Sample Preparation for Hemostasis Testing (F) Flashcards
What are the required blood collection tubes to be used for sample preparation for hemostasis testing?
1) Lavender top (EDTA)
2) Blue top (Sodium citrate)
3) Blue top (CTAD)
What is the anticoagulant present in lavender top?
Ethylenediaminetetraacetic acid
What are the purposes of lavender top?
It is used for:
1) PLT ct
2) Evaluation of PLT morpholoogy
3) Molecular testing to detect mutations
Elevated Hcts does not require the what (in terms of lavender top)?
It does not require the adjustment of anticoagulant
What is the anticoagulant present in blue top (sodium citrate)?
3.2% sodium citrate
What are the purposes of blue top?
It is used for majority of tests and assays in hemostasis testing
What must be strictly followed (when it comes to blue top)?
The blood:anticoagulant ratio
What is the blood:anticoagulant ratio in blue top?
9:1
What is the volume of blood and anticoagulant if regular tubes are used (in terms of blue top)?
Regular tubes require 2.7 mL of collected blood to be mixed w/ 0.3 mL of sodium citrate
What is the volume of blood and anticoagulant for other tubes (in terms of blue top)?
Some use 1.8 mL of blood + 0.2 mL sodium citrate
What should be done if the Hcts are 55% and above (in terms of blue top)?
If the Hcts are of 55% and above, it require the adjustment of anticoagulant
What is the formula used (for blue top)?
C = (1.85 X 10^-3) (100 - Hct) V D = 0.3 - C
What are the components of the formula (for blue top) and what does these components stand for?
V = total volume of mixture in tube in mL Hct = hematocrit of blood in percent C = adjusted anticoagulant in mL D = discarded anticoagulant in mL
Provide an ex of computation (executing the formula; for blue top)
E.g. A pt for hemostasis testing has a Hct of 65%
C = (1.85 X 10^-3) (100 - Hct) V C = (1.85 X 10^-3) (100 - 65) 3 mL C = 0.19 mL sodium citrate must remain in the tube D = 0.3 mL - 0.19 mL D = 0.11 mL sodium citrate must be discarded
What is the anticoagulant present in blue top (CTAD)?
Citrate theophylline adenosine dipyridamole
What is the purpose of blue top (CTAD)?
It is used for special assays in determining PLT activation or coagulation activation
What is the frequency of usage of blue top (CTAD)?
It is rarely used
What should be done in EDTA-mixed whole blood (as a part of the steps after blood collection)?
It should be mixed in an automated roller mixer to maintain the distribution of blood elements within the sx
What is the alternative that can be used for EDTA-mixed whole blood whereas automated roller mixer is used to it (as a part of the steps after blood collection)?
Alternative: should be in a rack and must be mixed well before processing
What should be done (or what are the parameters that should be done or observed) to citrated-whole blood (as part of the steps after blood collection)?
1) It should be maintained in an upright position
2) It should be intactly sealed
3) It should be only placed at ambient temperatures (15 - 25 DC)
What are the purposes of whole blood + sodium citrate?
It is used for:
1) Lumiaggregometry
2) Electrical impedance conventional aggregometry
3) Thromboelastography (TEG)
4) Thromboelastometry (ROTEM)
What should be done to whole blood + sodium citrate prior to testing?
Gently invert the tube prior testing
What is the time duration of testing the citrated whole blood?
It should be tested within 4 hrs at 15 - 25 DC
What should be done (in terms of storage) to EDTA whole blood if the sx will be used for automated or manual CBC?
1) It can be stored up to 6 hrs if it is at room temp
2) It can be stored up to 24 hrs if it is at 4 DC
If the sx (EDTA whole blood) will be used for PLT morphology in blood film, what should be done to the sx (in terms of preparation)?
The sx should be prepared within 3 hrs at room temp
What is PLT-rich plasma?
It is described as a plasma w/ 200,000 - 300,000/uL of PLTs
What are the uses of PLT-rich plasma?
It is used for:
1) Light transmittance conventional aggregometry
2) Lumiaggregometry
What is the process (or steps) to acquire PLT-rich plasma(?)?
1) Centrifuge tube at 50 x g for 30 mins
2) Transfer supernatant using a plastic pipette to a plastic tube
3) Stand undisturbed for 30 mins to regain responsiveness
What are the components of the mixture (inside the test tube) for acquiring PLT-rich plasma?
1) PLT-Poor Plasma
2) PLT-Rich Plasma
3) RBCs
What is the time duration for testing of PLT-rich plasma?
It should be tested within 4 hrs at 15 - 25 DC
What is PLT-poor plasma?
It is described as plasma w/ < 10,000/uL of PLTs
What is the use of PLT-poor plasma?
It is used for clot-based coagulation tests
What is the process (or steps) to acquire PLT-poor plasma?
1) Centrifuge tube at 1,500 x g for 15 mins
* if HemoCue StatSpin centrifuge is used, spin at 4,400 x g for 3 mins
What should be done if the pt is not taking unfractionated heparin (centrifuged or uncentrifuged; for PLT-poor plasma) in correlation to tests?
PT: tested within 24 hrs at 15 - 25 DC
PTT: tested within 4 hrs at 15 - 25 DC
Factor assays: tested within 4 hrs at 15 - 25 DC
What should be done if the pt is taking unfractionated heparin (centrifuged within 1 hr; for PLT-poor plasma) in correlation to tests?
PT: tested within 4 hrs at 15 - 25 DC
PTT: tested within 4 hrs at 15 - 25 DC
What should be done if the sx will not be processed within the day (centrifuged within 1 hr; for PLT-poor plasma) in correlation to tests?
1) It can be stored until 2 wks if it is at -20 DC
2) It can be stored until 6 mos or beyond if it is at -70 DC
3) THAWING: thaw plastic tube at 37 DC, mix, should be tested within 1 hr
What is double spin PLT-poor plasma?
It is described as a plasma w/ < 5,000/uL of PLTs
What is the characteristic of double spin PLT-poor plasma?
It is preferred for lupus anticoagulant testing
What is the process (or steps) to acquire double spin PLT-poor plasma?
1) Centrifuge tube at 1,500 x g for 15 mins
2) Transfer supernatant using a plastic pipette to a plastic tube
3) Centrifuge a plastic tube at 1,500 x g for 15 mins
What is the preparation done to citrated whole blood?
Gentle inversion before testing
What is the stability of citrated whole blood for electrical impedance conventional aggregometry and lumiaggregometry?
Electrical impedance conventional aggregometry: tested within 4 hrs at 15 - 25 DC
Lumiaggregometry: tested within 4 hrs at 15 - 25 DC
What is the preparation done to EDTA-mixed whole blood?
Gentle inversion before testing
What is the stability of EDTA-mixed whole blood for CBC and PLT morphology in blood film?
CBC: can be stored up to 6 hrs if it is at room temp
CBC: can be stored up to 24 hrs if it is at 4 DC
PLT morphology in blood film: should be prepared within 3 hrs at room temp
What is the preparation done to PLT-rich plasma?
Centrifuge tube at 50 x g for 30 mins
What is the stability of PLT-rich plasma for light transmittance conventional aggregometry and lumiaggregometry?
Light transmittance conventional aggregometry: tested within 4 hrs at 15 - 25 DC
Lumiaggregometry: tested within 4 hrs at 15 - 25 DC
What is the preparation done to PLT-poor plasma?
Centrifuge tube at 1,500 x g for 15 mins
What is the stability of PLT-poor plasma if pt is not taking unfractionated heparin (centrifuged or uncentrifuged)?
PT: tested within 24 hrs at 15 - 25 DC
PTT: tested within 4 hrs at 15 - 25 DC
Factor assays: tested within 4 hrs at 15 - 25 DC
What is the stability of PLT-poor plasma if the pt is taking unfractionated heparin (centrifuged within 1 hr)?
PT: tested within 4 hrs at 15 - 25 DC
PTT: tested within 4 hrs at 15 - 25 DC
What is the stability of PLT-poor plasma if sx will not be processed within the day (centrifuged)?
1) It can be stored until 2 wks if it is at -20 DC
2) It can be stored until 6 mos or beyond if it is at -70 DC
What are the diff sx collection errors for hemostasis testing?
1) Underfilled citrate tubes
2) Overfilled citrate tubes
3) Elevated Hct
4) Clotted sx
5) Visible hemolysis
6) Lipemia (cloudy or milky) or icterus (yellow)
7) Tourniquet > 1 min
What is the result for underfilled citrate tubes?
Prolonged clot-based time tests
What is the result for overfilled citrate tubes?
Shortened clot-based time tests
What is the result for elevated Hct?
Prolonged clot-based time tests
What is the result for clotted sx?
Prolonged clot-based time tests
What is the result for visible hemolysis?
Results are not detected by optical instruments for clot-based time tests; in vitro activation of primary and secondary hemostasis
What is the result for lipemia (cloudy or milky) or icterus (yellow)?
Results are not detected by optical instruments for clot-based time tests; results are also not detected by chromogenic assays
What is the result for tourniquet > 1 min?
Shortened clot-based time tests
What are the sx storage errors encountered in hemostasis testing?
1) Storage at 1 - 6 DC
2) Storage > 25 DC
3) Removed blood collection seal
What is the result for storage at 1 - 6 DC?
Prolonged clot-based time tests due to in vitro activation of PLTs and factor VII and precipitation of VWFs
What is the result for storage > 25 DC?
Prolonged clot-based time tests due to deterioration of factors V and VIII
What is the result for removed blood collection seal?
Prolonged clot-based time tests due to increased pH