AAB BASIC KNOWLEDGE LLATEST 2026 EVALUATION TEST
QUESTIONS AND SOLUTIONS RATED A+
✔✔Difference between plasma and serum - ✔✔plasma retains fibrinogen (clotting
component) which is removed from serum
✔✔Tubes used for whole blood (7 tubes) - ✔✔Blue top: 3.2% sodium citrate
Purple/lavender top: EDTA
Green top: Heparin
Yellow top: SPS (for microbiology fluids and blood)
Yellow top: ACD Solution B (for genetic & chromosomal analysis, flow cytometry)
Navy blue top: EDTA (for lead)
Gray top: potassium oxalate/sodium fluoride
✔✔Serum or plasma may be cloudy due to - ✔✔chronic or transient high lipid levels in
patients blood
✔✔To avoid dietary-induced high lipid levels prior to testing - ✔✔require patients to
exclude the high-fat foods from their diets or to fast for 12-14 hours prior to specimen
collection
✔✔Hematology specimens need to be tested - ✔✔within 24 hours
✔✔Lipemia - ✔✔can falsely elevate some liver enzymes result (ALT and AST)
✔✔Recommended order of blood collection tubes - ✔✔1. Blood culture tubes
2. non-additive tube
3. coagulation tube
4. additive tubes
✔✔Order of additive tubes - ✔✔1. serum separator tube
2. heparin (sodium heparin first then lithium heparin)
c. EDTA
d. oxalate/fluoride
✔✔Why must blood collection tubes be drawn in a specific order? - ✔✔to avoid cross-
contamination of additives between tubes and to maintain sterility when blood cultures
are drawn
✔✔What color is normal serum or plasma - ✔✔clear and light yellow to straw
✔✔What color is turbid serum or plasma - ✔✔cloudy or milky
, ✔✔Lithium Heparin tube - ✔✔-tubes typically contain spray-coated lithium heparin and
a gel for plasma separation
-used for making plasma determinations in chemistry
-eliminate the need to wait for a clot to form, making it an ideal tube for STAT
procedures, as well as for patients receiving anticoagulant therapy
✔✔K2 EDTA & K3 EDTA tubesi - ✔✔-used for whole blood hematology determinations,
immunohematology testing & blood bank testing
-require 8-10 inversions for thorough mixing of blood with anticoagulant
-whole blood should never be frozen, as freezing will cause red blood cells to hemolyze
✔✔Reasons K2 EDTA was chosen over K3 EDTA - ✔✔1. K3 EDTA results in greater
RBC shrinkage
2. K3 EDTA produces a larger increase in cell volume on standing
3. K3 EDTA is a liquid additive and will result in the dilution of the specimen
✔✔Serum (Silica) tubes - ✔✔-used for serum determinations in chemistry, serology,
immunohematology, and blood bank
-used for tests where the gel serum separator interferes with test metholodology
✔✔Heparin tubes - ✔✔-may be either lithium heparin or sodium heparin
-used for plasma determinations in chemistry
✔✔Citrate tubes - ✔✔-used for routine coagulation studies
-have 3.2% buffered sodium citrate solution
-used primarily for coagulation testing must be filled to the required volume of the tube
in order to maintain the appropriate concentration of citrate anticoagulation in the
plasma to be tested
✔✔Fluoride tubes - ✔✔-contain a glycolytic inhibitor and are used for glucose
determination on plasma
-useful if the glucose to be tested hours later
-if serum or plasma separator is used and glucose analyzed soon after blood draw,
glucose is OK and a fluoride tube is not necessary
✔✔Red-stopper tube - ✔✔-contains no anticoagulant or preservative
USE: serum or clotted whole blood
-serum must be separated from cells within 45-60min of venipuncture
✔✔Marbled red/gray or red-stopper, gold, serum separator tube tube (SST) - ✔✔-
contains clot activator and gel for separating serum from cells, but not anticoagulant
USE: serum
-serum must be separated within 45 min
-if specimen is centrifuged before clotting is complete, a fibrin clot will form on top of
cell; this finding is frequent in hemolyzed specimens
QUESTIONS AND SOLUTIONS RATED A+
✔✔Difference between plasma and serum - ✔✔plasma retains fibrinogen (clotting
component) which is removed from serum
✔✔Tubes used for whole blood (7 tubes) - ✔✔Blue top: 3.2% sodium citrate
Purple/lavender top: EDTA
Green top: Heparin
Yellow top: SPS (for microbiology fluids and blood)
Yellow top: ACD Solution B (for genetic & chromosomal analysis, flow cytometry)
Navy blue top: EDTA (for lead)
Gray top: potassium oxalate/sodium fluoride
✔✔Serum or plasma may be cloudy due to - ✔✔chronic or transient high lipid levels in
patients blood
✔✔To avoid dietary-induced high lipid levels prior to testing - ✔✔require patients to
exclude the high-fat foods from their diets or to fast for 12-14 hours prior to specimen
collection
✔✔Hematology specimens need to be tested - ✔✔within 24 hours
✔✔Lipemia - ✔✔can falsely elevate some liver enzymes result (ALT and AST)
✔✔Recommended order of blood collection tubes - ✔✔1. Blood culture tubes
2. non-additive tube
3. coagulation tube
4. additive tubes
✔✔Order of additive tubes - ✔✔1. serum separator tube
2. heparin (sodium heparin first then lithium heparin)
c. EDTA
d. oxalate/fluoride
✔✔Why must blood collection tubes be drawn in a specific order? - ✔✔to avoid cross-
contamination of additives between tubes and to maintain sterility when blood cultures
are drawn
✔✔What color is normal serum or plasma - ✔✔clear and light yellow to straw
✔✔What color is turbid serum or plasma - ✔✔cloudy or milky
, ✔✔Lithium Heparin tube - ✔✔-tubes typically contain spray-coated lithium heparin and
a gel for plasma separation
-used for making plasma determinations in chemistry
-eliminate the need to wait for a clot to form, making it an ideal tube for STAT
procedures, as well as for patients receiving anticoagulant therapy
✔✔K2 EDTA & K3 EDTA tubesi - ✔✔-used for whole blood hematology determinations,
immunohematology testing & blood bank testing
-require 8-10 inversions for thorough mixing of blood with anticoagulant
-whole blood should never be frozen, as freezing will cause red blood cells to hemolyze
✔✔Reasons K2 EDTA was chosen over K3 EDTA - ✔✔1. K3 EDTA results in greater
RBC shrinkage
2. K3 EDTA produces a larger increase in cell volume on standing
3. K3 EDTA is a liquid additive and will result in the dilution of the specimen
✔✔Serum (Silica) tubes - ✔✔-used for serum determinations in chemistry, serology,
immunohematology, and blood bank
-used for tests where the gel serum separator interferes with test metholodology
✔✔Heparin tubes - ✔✔-may be either lithium heparin or sodium heparin
-used for plasma determinations in chemistry
✔✔Citrate tubes - ✔✔-used for routine coagulation studies
-have 3.2% buffered sodium citrate solution
-used primarily for coagulation testing must be filled to the required volume of the tube
in order to maintain the appropriate concentration of citrate anticoagulation in the
plasma to be tested
✔✔Fluoride tubes - ✔✔-contain a glycolytic inhibitor and are used for glucose
determination on plasma
-useful if the glucose to be tested hours later
-if serum or plasma separator is used and glucose analyzed soon after blood draw,
glucose is OK and a fluoride tube is not necessary
✔✔Red-stopper tube - ✔✔-contains no anticoagulant or preservative
USE: serum or clotted whole blood
-serum must be separated from cells within 45-60min of venipuncture
✔✔Marbled red/gray or red-stopper, gold, serum separator tube tube (SST) - ✔✔-
contains clot activator and gel for separating serum from cells, but not anticoagulant
USE: serum
-serum must be separated within 45 min
-if specimen is centrifuged before clotting is complete, a fibrin clot will form on top of
cell; this finding is frequent in hemolyzed specimens
