BLOOD COLLECTION Flashcards
Most common site for venipuncture
antecubital fossa (median, cephalic, basilic)
Cleansing motion for site
friction of back and forth
Angle between skin and needle during venipuncture
<30 degrees
Maximum tourniquet application time
<1 minute (60 seconds)
Cause of specimen hemolysis
prolonged tourniquet, moisture/contam in blood tube, needles with small bores, excessive agitation, frothing
Effect of prolonged tourniquet application
false shortening of coagulation test due to stasis, FVIII, and VWF accumulation
Distance of tourniquet from puncture site
3-4 inches (7.5-10 cm)
Most common needle size for adult venipuncture
21 G; 1-inch length
Maximum number of punctures allowed
2
When to replace sharp container
no more than three-quarters full
Most common cause of needle puncture injury
improper disposal
Usual EDTA anticoagulant component
Dipotassium (K2)
CBC is also called
hemogram
Optimal EDTA anticoagulant concentration
1.5 mg/mL of blood
Time to analyze CBC specimen
6 hours (room temp); 24 hours (refrigerated)
Time to prepare blood smear
within 3 hours
EDTA prevents
platelet aggregation
Effect of EDTA on platelets in 1 hour
20% increase in size
Excessive EDTA causes
decreased HCT, ESR; WBC degeneration; increased MCHC
RBC parameters
RBC count, Hgb, Hct, RBC indices, RDW, Retic count
WBC parameters
WBC count, neut, lymph, mono, eo, baso (relative and absolute)
Platelet parameters
Platelet count, Mean platelet volume
Definition of chelation
ring-shaped molecular complex binding metal ions
Delta check definition
current test result compared to previous test result for same patient
