Specimen collection and processing Flashcards
Heel stick is used for
Newborn screening
Serum samples are collected in
Gold colored capped vacutainer tubes
Plasma is the non cellular component of anticoagulated/coagulated blood gotten after ………………..
Anticoagulated
Centrifugation of the whole sample
Serum samples are mostly used for running
Immunoassays
Anticoagulants in Clinical Pathology labs
Heparin
EDTA
Sodium fluoride
Heparin is available as lithium heparin and sodium heparin in
green capped vacutainer tubes
Heparin accelerates the action of
Antithrombin III, preventing the formation of fibrin
EDTA is mostly used in
Hematology tests and DNA studies
EDTA is available in
Lavender capped vacutainer tubes
Sodium fluoride inhibits what enzyme in glycolysis
Enolase enzyme
Sodium fluoride is used for collecting samples for
Glucose assay
Sodium fluoride is available in
Grey capped vacutainer tubes
What anticoagulants form insoluble complexes with Calcium ions
Oxalates
Oxalates are often mixed with
Fluoride in grey capped vacutainer tubes
What anticoagulant inhibits glycolysis
Sodium iodoacetate
Sodium Citrate is used for
Coagulation profile testing. Converts calcium to non ionized form
Tubes of Sodium Citrate are
light blue capped vacutainer tubes
Standard tubes used in chemistry labs are of two types
Vacutainer
Ordinary
Match the Anticoagulants with the colors of the caps of their ordinary tubes
Lithium heparin- deep blue
EDTA- Green
Fluoride oxalate- Yellow
Plain tube- Red
Order of draw
- Sterile tubes
- Coagulation study tubes
- EDTA tubes
- Heparin tubes
- Fluoride oxalate
- Serum sample tube
SCEHFS
Interference can be as a result of
Haemolysis
Icteria
Lipaemia
Lipaemia may be visible at Serum triglyceride concentration above
300mg/dl
Lipaemic interferences can be reduced by
- Ensuring at least 12hrs of fasting before sample collection
- Ultracentrifugation of samples at speed of 10000g
Icteric samples result when
Concentration of bilirubin is elevated
To reduce the effect of spectral bilirubin interferences,
Run the sample blank alongside
What analytes are affected by haemolysis
Potassium
Phosphorus
ALT
Acid phosphatase
What is used to reduce the effect of sample haemolysis
Sample blanking
Samples for what essay should be protected from light
Bilirubin to prevent photo degradation
Uncentrifuged samples should not be frozen before separation T/F
T
To avoid haemolysis
Anticoagulated blood samples should be centrifuged at what speed and time
15 minutes
2000-3000g
Clotted whole blood should be centrifuged at what time and speed
30 minutes
1500g
Samples should be lower the room temperature before the start of centrifuging T/F
F
Specimens should be stored at what temperature
-20C, then -80C
CSF is used to determine
Cell count, Glucose, Proteins estimation
Establishing a reference interval would require how many individuals (REFERENCE INTERVALS)
120 to greater than 700
Verifying a reference interval (transference) can require how many study individuals (REFERENCE INTERVALS)
20
