Order of Draw Quiz
Questions: 16 · 10 minutes
1. A serum specimen shows unexpectedly high potassium and low calcium after it was collected following a lavender tube. Which preanalytical error best fits this pattern?
Fluoride carryover from a gray tube
Citrate carryover from a light-blue tube
Heparin carryover from a green tube
EDTA carryover from the lavender tube
2. What is the main purpose of following the venous order of draw?
To make every specimen clot at the same rate
To ensure the largest tube is always filled first
To reduce additive carryover that could alter later specimens
To eliminate the need to mix additive tubes
3. A red serum tube, a gold serum-separator tube, and a green heparin tube are ordered. Which statement correctly describes their placement?
The green tube must be collected between the red and gold tubes
The green tube comes first because anticoagulant tubes precede serum tubes
The gold tube belongs after the green tube because it contains gel
Both serum tubes belong before the green heparin tube
4. A winged blood-collection set is used, and a light-blue citrate tube is the first and only requested specimen. Why may a discard tube be collected first?
To remove EDTA that is routinely stored inside the collection tubing
To fill the set's tubing so the citrate tube can reach its required blood volume
To make the patient's blood clot before the citrate tube is attached
To test whether the serum will separate correctly
5. A lavender EDTA tube is mistakenly collected before a serum tube. Which contamination pattern is most associated with EDTA carryover into the serum specimen?
Decreased glucose with increased sodium
Falsely increased potassium with decreased calcium
Increased calcium with shortened clotting time
Decreased potassium with increased magnesium
6. When a discard tube is needed before a light-blue citrate tube used with a winged set, how does that discard tube function in the sequence?
It is collected after the citrate tube and sent for chemistry testing
It is collected first to prime the tubing and is not used for the ordered analysis
It replaces the citrate tube if it fills to the required line
It must contain EDTA to prevent clot formation in the tubing
7. A patient needs blood cultures, a light-blue citrate tube, and a gold serum-separator tube. In what order should they normally be collected?
Blood cultures, light blue, gold
Light blue, blood cultures, gold
Blood cultures, gold, light blue
Gold, light blue, blood cultures
8. Blood cultures and a light-blue citrate tube are requested during the same venipuncture. Which specimen normally has priority in the order of draw?
The light-blue tube because its fill volume is critical
Blood cultures because sterile specimens are collected before citrate tubes
The specimen with the shortest laboratory turnaround time
Whichever specimen appears first on the requisition
9. You notice that a lavender EDTA tube was drawn immediately before a light-blue citrate tube. What is the most appropriate response?
Submit the citrate tube without noting the error because both tubes prevent clotting
Pour part of the citrate specimen into a new tube to dilute possible EDTA
Follow facility procedure for reporting the error and determine whether the citrate specimen must be recollected
Shake the citrate tube vigorously to neutralize any carried-over additive
10. How should tube mixing be integrated with the order of draw?
After each tube is filled, gently invert it as specified for that tube while maintaining the collection sequence
Mix only the final tube because earlier tubes have already contacted blood
Collect every tube first, then shake all tubes together at the end
Do not mix additive tubes unless a visible clot begins to form
11. A royal-blue trace-element tube is requested. What determines where it belongs in the order of draw?
Its label color alone, placing it after all other blue-colored tubes
The trace element being measured, regardless of the tube's additive
Its physical size, with larger royal-blue tubes collected first
Its additive, such as clot activator, heparin, or EDTA
12. Only a gold serum tube, a green heparin tube, and a lavender EDTA tube are ordered. Which sequence is correct?
Green, gold, lavender
Lavender, green, gold
Gold, lavender, green
Gold, green, lavender
13. A light-blue citrate tube and a lavender EDTA tube are both ordered, with no blood cultures or serum tubes. What is the correct relative order?
Lavender first because hematology tubes precede coagulation tubes
Either order is acceptable because both contain anticoagulants
Light blue first, then lavender
Lavender first, followed by a discard tube and then light blue
14. The orders are blood cultures, a gold serum tube, a lavender EDTA tube, and a gray fluoride/oxalate tube. No citrate or heparin tube is needed. Which sequence is correct?
Blood cultures, gold, lavender, gray
Gold, blood cultures, gray, lavender
Blood cultures, lavender, gold, gray
Lavender, gold, blood cultures, gray
15. After filling a green heparin tube, you still need a lavender EDTA tube and a gray fluoride/oxalate tube. Which should come next?
Gray, then lavender
Either one; their additives cannot affect each other
Lavender, then gray
Collect another green tube before either one
16. For a routine venipuncture using standard evacuated tubes, which sequence follows the standard order of draw?
Blood cultures, light blue, serum, green, lavender, gray
Light blue, blood cultures, serum, lavender, green, gray
Blood cultures, serum, light blue, green, gray, lavender
Serum, blood cultures, light blue, lavender, green, gray