Additives

Question 1

EDTA

Answer 1

Ethylenediaminetetraacetic acid
Available as a powdered di-potassium or liquid tri-potassium salt
Prevents coagulation by binding or chelating calcium
Preserves cell morphology and inhibits platelet aggregation
Additive in lavender (regular and micro collection, pink, pearl-top tubes and royal blue top with lavender color coding
Inverted 8-10 times

Question 2

Citrate

Answer 2

Sodium citrate
Prevent coagulation by binding or chelating calcium
3-4 inversions
Fill within 90 percent of stated volume to contain a 9:1 ratio (blood to anticoagulant)
Coagulation tests are performed on plasma
Calcium is added back to the specimen during testing processing

Question 3

Heparin

Answer 3

Prevents clotting by inhibiting thrombin (an enzyme needed to convert fibrinogen into the fibrin necessary for clot formation) formation
Eliminates need for specimen to clog before serum could be obtained
Green top, light green top, royal blue with green color coding on label, green and light green microtubes
Cannot be hemolyzed
Invert 5-10 times

Question 4

Sodium polyaethol sulfonate (SPS)

Answer 4

Prevents coagulation by binding calcium, reduces the action of a protein called complement which destroys bacteria, slows down phagocytosis and reduces the activity of certain antibiotics
Used in blood culture collection
Requires 8 inversions to prevent clotting

Question 5

Citrate phosphate dextrose (CPD)

Answer 5

Used in collecting blood for transfusion
Prevents clotting by chelating calcium, phosphate stabilizes pH and dextrose provides cells with energy and helps keep them alive

Question 6

Acid citrate dextrose (ACD)

Answer 6

Used for immunohematology tests such as DNA testing and human leukocyte antigen (HLA) phenotyping (paternity testing and transplant compatibility)
Acid citrate prevents coagulation, dextrose acts as a RBC nutrient and preserves viability
Requires 8 inversions

Question 7

Oxalate

Answer 7

Prevents coagulation by precipitating calcium
Commonly added to tubes containing glucose preservation
Must be mixed immediately
8-10 inversions

Question 8

Sodium fluoride

Answer 8

Antiglycolytic agent (prevents the glycolysis or the breakdown or metabolism of glucose by blood cells)
Preserves glucose for up to 3 days and inhibits bacteria growth
Requires 5-10 inversions

Question 9

Clot activator

Answer 9

Substance that enhances coagulation in tubes used to collect serum specimens

Question 10

Silica (glass) particles and inert clays (like Celite)

Answer 10

Clot activator - within 15-30 min
In serum separator tubes (SSTs) and red tip tubes
5 gentle inversions

Question 11

Thixotrophic gel

Answer 11

An inert (non-reacting) synthetic substance initially contained in or near the bottom of certain blood collection tubes