AAB Molecular Review questions and answrs(latest update)

What are the the 2 recommended anticoagulants for Plasma or Bone Marrow Aspirate Samples EDTA and ACD Why is EDTA one of the recommended coagulants for Plasma or Bone marrow aspirate samples 1)A chelating (binding) agent for divalent cations such as Mg++ or Ca++ 2)Helps deactivate metal-dependent enzymes 3)Suppresses damage to DNA and proteins by deoxyribonucleases 4)Allows DNA to remain in native state and large molecular size before extraction What does EDTA stand for? ethylenediaminetetraacetic acid What does ACD stand for? Acid Citrate Dextrose Why is ACD also one of the recommended anticoagulants used for Plasma and Bone marrow Aspirate 1)Like EDTA, gets rid of CA++ ions How many types of ACD tubes are there? 2 types A and B ACD Type A Has more trisodium citrate, citric acid, and dextrose -Used for DNA, RNA, and PFGE -Blood Preservative -Capable of maintaining normal platelet responsiveness up to 6-8 hrs because it preserves clotting factors -Also a good RBC preservative ACD Type B Similar to ACD Type A however in smaller amounts and therefore less effective as a preservative Why are Heparin tubes not used as often for molecular testing Potent PCR inhibitor -Inhibits enzymes such as RT and DNA polymerases Lavender top tube (Molecular testing) EDTA -Used for hematology, BB, and chemistry -DNA and RNA isolation -Can be stored up to ~72 hrs at 4 degrees without DNA degradation Yellow top tube(Molecular testing) ACD -Used for reference testing -Acceptable DNA isolation(must be processed within 24 hrs) -Used to store whole blood Green top tube Contains Heparin -Used for chemistry and certain hematology -Does not work for isolation methods -Will compromise RNA isolation -Must be processed within 24 hrs What are 3 main molecular specimen sample types A)Bone Marrow B)Peripheral Blood C)Tissue Bone Marrow as a sample type for Molecular Testing ~2-3 cc-1 mL -Preferred in lavender tubes -Accepted in yellow top tubes Peripheral Blood as a sample type for Molecular Testing ~10-30 cc -Preferred in lavender tubes Tissue as a sample type for Molecular Testing (3 mm x 3mm x 3mm) in PBS (Phosphate buffered saline) NOTE:For transport, PBS is drained and shipped in either dry ice or 70% ethanol----USE AT ROOM TEMP Storage should be 4 degrees Preferred transport time for DNA and RNA -Avoid extreme temperatures -For RNA-Ship overnight -For DNA-Ship overnight is preferred Avoid hemolysis Preferred to separate WBCs from whole blood for transport for extraction Why do we want to avoid hemolysis in respect to whole blood extraction? RBCs, when lysed, release heme which is a PCR inhibitor Delivery requirements for blood serum -Separate from cells and freeze immediately to preserve RNA viruses -~1-2mL -Should be shipped Frozen or in dry ice for RNA and RNA studies Delivery requirements for Plasma -Stable up to 5 days 2-5 degrees and longer if frozen -Shipped at 2-5 and stored at -20 -For RNA studies, extraction must begin within 4 hrs or specimen should be frozen Delivery requirements for Bone Marrow -Handle like whole blood -Usually need and get smaller samples -Store at -20 -Stable for 2 weeks