Hemostasis Specimen Collection Flashcards
• Laboratory procedures are performed on _______________ by a ________.
- venous whole blood collected
- venipuncture
• mixed 9:1 with a 3.2% solution of _____________.
sodium citrate anticoagulant
• The specimen is maintained as well-mixed whole blood for platelet function testing or centrifuged to provide _______________
platelet poor plasma
Clotting / Bleeding History
- Blood group O – High risk vWD
- Pregnancy ( Prothrombotic)
- Liver / Kidney disease
- leukemia / anemia
Clotting / Bleeding Characteristic
- Location
- Frequency
- Volume
Drug History
Anticoagulant ( blood thinners)
Antiplatelet (aspirin)
Contraceptives
Dietary / Over the counter / Dietary Supplement
- Garlic , Ginger
discontinue non prescription drug at least a week blood collection
Vit K
_________ such as _______ or _____________ and antiplatelet drugs such as ASA or clopidogrel are continued when the purpose is to assess their efficacy.
- Anticoagulant
- Coumadin
- direct oral anticoagulants
Patients need only fast under arranged circumstances but are advised to avoid caffeine
and exercise for 2 hours and smoking for 30
minutes before collection. Patients should be
inactive for 5 minutes before collection.
Fasting
Adult with good veins, specimen less than or equal 25 mL
20 or 21 gauge, thin-walled, 1.0 or 1.25 inches long
Adult with good veins, specimen greater than or equal 25 mL
19 gauge, 1.0 or 1.25 inches long
Child or adult with small, friable, or hardened veins
23 gauge, winged-needle set:
apply minimal negative pressure
Transfer of blood from syringe to tube
19 gauge, slowly inject through tube closure
Syringe with winged-needle set
20, 21, or 23 gauge, thin walled:
use only for small, friable, or hardened veins or specializes coagulation testing
Most hemostasis specimens are collected in
_________ (________, _________) sterile evacuated blood collection tubes containing a measured volume of ________________________ anticoagulant.
- Hemostasis Specimen Collection Tubes
- plastic blue-stopper
- (blue-top, blue-closure)
- 0.105 to 0.109 M (3.2%) buffered sodium citrate
◦ Sodium Citrate
◦ The anticoagulant used for hemostasis testing is buffered 3.2% (0.105 to 0.109 M) __________, _________.
◦ The anticoagulant solution is mixed with blood to produce a 9:1 ratio: __________________.
◦ In most cases, 0.3 mL of anticoagulant is mixed with 2.7 mL of whole blood,
- Anticoagulant used for Hemostasis
- sodium citrate, Na3C6H5O7
- 9 parts whole blood to 1 part anticoagulant
The _______________ is effective, provided the patient’s hematocrit is 55% or below.
9:1 blood-to-anticoagulant ratio
In __________ the decrease in plasma volume relative to whole blood unacceptably raises the anticoagulant-to-plasma ratio, which causes
falsely prolonged results for clot-based coagulation tests.
polycythemia
The _________ must prepare specially marked tubes with relatively reduced anticoagulant volumes for collection of blood from a patient whose hematocrit is known to be ___________.
- phlebotomist
- 55% or higher
The amount of anticoagulant may be computed by using this formula:
C= (1.85 x10-3) (100-HCT) V
• Remove the stopper from a 3-mL blue closure
collection tube, pipette and ______________ of anticoagulant, leaving 0.19 mL.
discard 0.11 mL from the 0.3 mL
Collect blood in a syringe and ___________________, ___________, and _____________ at least three times.
- transfer 2.81 (2.8) mL of blood to the tube
- replace the stopper
- immediately mix by gently inverting
- Don’t preserve _________
- Inhibits ___________
- Only for _________
- not for ___________
- EDTA
- labile clotting factors
- thrombin-fibrinogen reaction
- platelet count
- coagulation studies
- Binds with ________
- Inhibits ______________
- For __________/___________
- Heparin
- anti-thrombin III
- all reactionsin coagulation
- platelet retention test/glass bead retention test only
- Shortened clotting time because it forms
insoluble ________/_________ - Affects _______________
- Oxalates
- complexes/precipitates
- photo-optical clot detection
Although _________ discourages the practice, specimens may of necessity be collected from ______ or ________, ports in __________, ____________, ______________, or ____________.
- CLSI Standard
- heparin or saline locks
- intravenous (IV) lines
- peripherally inserted central catheters (PICC tubes)
- central venous catheters
- dialysis catheters
•Before blood is collected for 8 __________, the line must be flushed with _________, and the __________, or ____________________, must be _________ and __________.
- hemostasis testing
- 5 mL of saline
- first 5 mL of blood
- six times the volume of the blood collection tube
- collected and discarded
• The key to ______________________.
accurate capillary PT/INR measurement is a free- flowing puncture
Often it is necessary for the collector to __________________ to the fingertips.
warm the patient’s hand to increase blood flow
The collector ___________ (“_______”) ________, because this ______________
- avoids squeezing (“milking”) the finger
- raises the concentration of tissue fluid relative to plasma and blood
Short draw
Whole-blood volume less than 90% of required volume or less than manufacturer specified minumum
Clot in specimen
Each specimen musy be visually inspected prior to centrifugation; the presence of even a small clot requires that the specimen be recollected.
Visible hemolysis
Hemolysis, pink or red plasma indicates in vitro activation of platelets and coagulation. Results are unreliable.
Lipemia or icterus
Optical instruments may not measure clots in cloudy or highly colored specimens, specially chromogenic substrate methods. The practitioner must employ a mechanical instrument.
Prolonged tourniquet application
Stasis elevates the concentration of von Willebrand factor and factory Vlll; falsely decreases fibrinolyric parameters, and falsely shorten clot-based results
Specimen storage at 1°C to 6° C
Storage at refrigerator temperatures causes preciptation of large von Willebrand factor multimers, activation of coagulation factor Vll, and destroys platelet integrity
Specimen storage at more than 25° C
Storage at above standard room temperature causes coagulation factors V and Vll! to deteriote
___________________ whole blood specimens are placed in a rack and allowed to stand in a vertical position with the closure intact and uppermost.
Sodium citrate-anticoagulated
Maintaining the blood collection tube seal minimizes ________, which otherwise allows the pH to rise, falsely prolonging the __ and ____.
- CO2 diffusion
- PT and PTT
Specimens are maintained at ambient temperature, __________, never at refrigerator temperatures or on ice.
15° C to 25°C
Storage at _______________, _____________, and __________________.
- 1° C to 6° C activates factor VII
- activates platelets
- precipitates large VWF multimers
Specimens are never stored or transported at temperatures ______________ because heat deteriorates coagulation factors ___ and ____.
- greater than 25° C
- V and VIII
Specimens collected for PT testing may be held at _____________ and ____________ of the time of collection.
- 18° C to 24° C
- tested within 24 hours
PT with no UFH
- 15° C-25° C
- Test within 24 hr, maintain upright and sealed
PTT with no UFH
Test within 4 hr, maintain upright and sealed
PTT for monitoring UFH
Centrifuge to separate plasma within 1 hour, test within 4 hr
PT when UFH is present
Centrifuge to separate plasma within 1 hour, test within 4 hr
Factor assays
Test within 4 hr, maintain upright and sealed
Optical platelet aggregometry using PRP
Wait 30 min after centrifugation, test within 4 hr of collection
Whole-blood aggregometry
Test within 4 hours of collection, maintain upright and sealed
Storage in household freezer
- -20° C
- 2 weeks
Storage for 6 months
- -70° C
- 6 months or indefinite
• Whole-Blood Specimens Used for ___________
• Must be collected with ___________ and held at __________
• Aggregometry should be started immediately and must be completed within ______ of specimen collection
• Most specimens for whole-blood aggregometry are mixed 1:1 with normal saline before testing, although if the platelet count is less than ___________ the specimen is tested undiluted.
- Preparation of Hemostasis Specimens for Assay
- Platelet Aggregometry
- 3.2% sodium citrate and 18°C to 24° C until testing
- 4 hours
- 100,000/mL
PPP
Platelet Poor Plasma
Plate count: ___________
<10x10⁹ platelets/L
Centrifuge: ____________
10-15 min, 2000-2500rpm
Test within _________
2 hours
Refrigerated temp: ___________
<4 hours
Freezing temp: ____________
-20 to 070° C
Used for ____________
coagulation studies
PRP
Platelet Rich Plasma
Platelet count: ___________
Centrifugation: ___________
- 250x109 platelets/L
- 10-15min, 60- 100rpm
Used for ________
platelet studies
Stored at ____________
room temperature
- Inhibits cyclooxygenase
- Platelet aggregation test:
- no intake within 7 days
- Bleeding time:
- no intake within 24 hours
Aspirin
- Affects cyclooxygenase
- Inhibits most clotting factors
Heparin
• Antagonist of prothrombin group and vitamin K dependent clotting factors
• Prevents gamma carboxylation of
◦ Vitamin K on clotting
Warfarin / Coumadin
◦ Alters blood vessels
• Induces hemolysis
Penicillin
- most potent penicillin capable of affecting platelet
- function
Carbenicillin
- Prematurely actives clotting process (extrinsic pathway)
- Must only be activated when reagent is added
Tissue thromboplastin contamination
Associated with collagen for in vitro activation of clotting process (instrinsic pathway)
Glass surfaces
- FV and FVlll: deteriorates if left at room temp for extended period of time
- FVll and FXl: prematurely activates at ref temp (4C)
Temperature
- Released tissue thromboplastin like substance that will activate clotting system
- Release ADP that causes platelet aggregation
Hemolysis
- Prolonged tourniquet application causes venous stasis
- Activates clotting factors
Tourniquet application
- Associated with loss of carbon dioxide that deteriorates clotting factors
- Sample must be unopened and tested within 6 hours
Increased pH
- Increases hematocrit by >50%
- Prolongs clotting time test
Polycythemia vera
- Blood to AC ration: 9:1 using 3.2% sodium citrate; 0.109m
- Citrate: anticoagulant of choice for coagulation studies
- Incomplete filling of tubes can result to increased amount of citrate (prolonged)
Amount of anticoagulant
