1 - proper sample storage and submission Flashcards
what is whole blood blood sample
an unspun, non-clotted sample. +/- anticoagulant. commonly used for CBCs
what is a plasma blood sample
plasma is the fluid fraction of whole blood obtained from an anticoagulated sample. Add anticoagulant then spin the blood down/ let it sit = fluid on top
- Blood without the cells just the fluid
what is a serum blood sample
serum is the fluid fraction of whole blood obtained from a clotted sample (loss of clotting factors).
- serum = plasma - fibrinogen (the clotting factor)
what is good sample storage
-plasma and serum should be stored properly if not being immediately used
- samples should be stored in the fridge and shipped on ice
- frozen for long term storage
- CBC samples should not be centrifuged or frozen. it is best to run ASAP or fridge for up to 72hrs
Explain EDTA purple top tube
EDTA anticoagulant - prevent coagulation by chelating calcium, gentle on cells
- used for CBCs
what are some common poor blood collection techniques
- Traumatic venipuncture = hemolysis or reduced platelet counts
- transfer into tubes too slow = blood will clot in syringe
- EDTA contamination if purple top is filled first
- plunging syringe when filling tubes causes increased pressure = hemolysis
- ensure proper volume of blood for anticoagulant
what happens when blood sits in the tube
it starts clotting immediately
explain heparin Green top tube
inhibits coagulation by potentiating antithrombin
- used for plasma (biochemistry)
explain citrate blue top
citrate = anticoagulant
reversibly prevents coagulation by weakly chelating ca
- used for coagulation testing
explain red top and white top tubes
Has no additives used for species dependent clotting time prior to centrifugation
- used for serum
white top - misc used for storage sample
explain tiger top tubes
Serum separator tubes
- contains gel w/ intermediate density btwn cells and serum or plasma
- upon centfugation the fluid fraction will be separated from the cell fraction, prevention leaching of certain analytes into the cell fraction.
**some tests like phenobarb levels are falsely decreased from fluid fraction contact with the gel separator
hemolysis in plasma/serum appearance changes
hemolysis results in free hemoglobin and subsequent red discoloration, may be in vitro or in vivo intravascular hemolysis
lipemia in plasma/serum appearance changes
results in a lactescent apperance, commonly observed in post-prandial samples and why sm animal pts should be fasted for blood draws
icterus in plasma/serum appearance changes
icterus represents elevated bilirubin and yellow discoloration, uses species specific rubrics. Lg animal plasma and serum naturally have a moderately yellow appearance
How can hemolysis plasma and serum appearance interfere with CBC results
- in vitro hemolysis falsely decrease PVC, Hct and RBC counts
- MCHC will be falsely elevated (HBG proportionally higher than Hct or PCV)
- Ghost erythrocytes form intravascular hemolysis may be falsely counted as platelets = increased platelet counts
- refractometric protein becomes difficult to read
how can hemolysis plasma and serum appearance interfere with chemistry results
- increase in intra- RBC analytes. Like potassium in horses, camelids and jap dogs. also phosphorus, ALT, LDH and Mg
- can cause a minimal to mild increase in creatine kinase (CK) enzymatic activity
how can hemolysis plasma/serum appearance interfere with electrophoresis results
sever hemolysis can cause beta globulin spikes
How can lipemia plasma/serum appearance interfere with CBC results
- falsely increased HGB and subsequently MCHC
- Lg lipid aggregated may be falsely counted as platelets and increase PLT or potentially leukocytes increased WBC
- falsely increased refractometric proteins
How can lipemia plasma/serum appearance interfere with chemistry results
- spectrophotometric interference
- proportional decrease in Na and Cl, slight decrease in K
what does lipemia promote in
blood samples
In vitro hemolysis
- samples can be refrigerated to precipitate out the liquid allowing collection of less lipemic serum/plasma
how does icterus plasma/serum samples interfere with CBC and chemistry samples
CBC : little to no effect
Chemistry: marked to severe hyperbilirubinemia falsely decreased biuret, total protein and creatinine
