CSMLS Interference Questions and Answers Already Passed

CSMLS Interference Questions and Answers Already Passed Why are serum separator tubes collected before the subsequent tubes in the order of draw? carryover of silica particles can be overridden by anticoagulants in tubes How does EDTA contamination affect chemistry results? Coagulation results? -Chem: increases K and Na; decreases Ca and iron -Coag: increases PT and PTT How does K oxalate affect hematology results? damages cell membranes and causes abnormal RBC morphology What anticoagulant interferes in enzyme reactions? potassium oxalate Why is heparinized plasma preferred over serum for potassium tests? when blood clots, potassium is released from cells into the serum and can falsely elevate results How does a short EDTA draw impact the CBC results? can cause RBCs to shrink therefore decreasing HCT What analytes may be elevated in a patient on a high protein diet? ammonia, urea, uric acid How would liquid EDTA impact CBC results? dilutes the sample and results in lower HGB, RBC and WBC counts and PLT counts How does heparin inhibit clot formation? inhibits thrombin (which cleaves fibrinogen to fibrin resulting in clot) as well as factor X Why is heparin commonly used for STAT testing? decreases TAT as you don't need to wait for the sample to clot before centrifuging What would happen if you had a short draw in a potassium oxalate? causes hemolysis and releases hemoglobin into plasma How does SPS inhibit the growth of bacteria? -reduces actions of complement proteins -slows down phagocytosis -reduces activity of certain antibiotics What impact do thiazide diuretics (blood pressure medication) have on analytes? -increase: calcium and glucose -decrease: sodium and potassium An overall healthy patient (no jaundice, no hemolysis in sample, other chemistry tests within range) has an increased K. What preanalytical error can cause this? -fist pumping -tourinquet too tight How long does complete clotting take at room temperature in SST? 30-60 minutes What are the storage requirements of a sample that cannot be tested within 8 hours? - serum/plasma should be separated and stored in the fridge -if testing cannot be performed beyond that, store in -20 What test typically requires a refrigerated stool sample? fecal fat What are the collection requirements for ammonia? -whole blood placed immediately on ice slurry -centrifuge within 15-20 minutes What analytes does fist clenching increase? Lactate, potassium, phosphate What analytes does prolonged tourniquet application increase? Calcium, cholesterol, lactate, enzymes, ammonia, albumin,