Hematology- sample collection and handling

What is plasma

• fluid portion of whole blood

• is 90% water and 10% dissolved constituents

Dissolved constituents of plasma

• protein

• carbs

• vitamins

• hormones

• enzymes

• lipids

• salts

• waste

• antibodies

• other irons and molecules

Serum

• is plasma without the fibrinogen (Blood cells and clotting elements)

Heparin

• an anticoagulant

• ratio of 20 U/mL of blood to be collected

• small amounts just to coat inside of syringe

EDTA tubes

• Anticoagulant

• Preferred for hematologic studies

  • Does not alter cell morphology

• Do not use plasma samples for chemical assays

• 1-2 mg/mL of blood

• Excessive amounts cause cells to shrink and invalidate cell counts in automatic analyzers

Oxalates

• anticoagulant

• Sodium, potassium, ammonium, or lithium salts

• postassium most common- not used in potassium assays

Citrates

• anticoagulant

• Sodium or lithium salts, sodium most used but interferes with sodium assays

Sodium fluoride

• bright blue

• glucose preservative

• 6-10mg/mL of blood

• May be added to other samples as a glucose preservatives

• interferes with many enzymatic tests

PCV in patients

• well hydrated animal

  • should have 50% PCV (50% water and 50% cells, 10mL blood = 5mL water )

• Dehydrated animal

  • PCV 70%, 70%cells and 30% fluid

  • 10mL blood = 3 mL fluid

Order of draw (in order, first to last)

• light blue (sodium citrate, coagulation studies)

• Red (serum for blood chemistry)

• tiger top (gel, seperator and clot activator)

• green (plasma for blood chemistry)

• lavender (hematology)

• gray (coagulation testing and glucose testing )