Pick a Tube
Order of Draw
Department
Requisition Form
Phlebotomy
100

A 9-year-old arrives confused, thirsty, and vomiting. The doctor wants a glucose level, and the specimen needs to be collected in a tube containing an antiglycolytic agent.

Which tube are you grabbing?

Gray-top tube — sodium fluoride/potassium oxalate

100

What color tube comes first?

Light Blue

100

A 9-year-old presents with recurrent epistaxis and prolonged bleeding after dental procedures.

The clinician orders tests to investigate the child's coagulation system.

Which laboratory department should you expect to process these tests?

Coagulation.

100

The requisition says:

“Collect at 8:00 AM.”

You arrive at 10:30 AM.

The patient is still there.

Do you simply collect the specimen?

Not without checking the test's timing requirements and following the laboratory/clinical instructions.

100

You've found the perfect vein.

You insert the needle...

and the vein rolls away like it has somewhere better to be. 

What technique can help prevent this?

Anchor the vein/skin with the non-dominant hand.

200

The lab asks for serum, not plasma.

You have: Red, Green, Lavender

Which tube would you pick and what's happening to the blood inside it?

Red — the blood is allowed to clot, producing serum.

200

Your patient needs:

  • Blood cultures
  • Glucose
  • Chemistry
  • PT/INR
  • CBC

What is the order of draw and what color are the tubes?

  • Blood cultures - yellow
  • PT/INR - light blue
  • Chemistry - red
  • CBC - lavender
  • Glucose - gray
200

A red-top tube containing serum arrives in the laboratory.

The clinician ordered electrolytes and renal function tests.

Which department is most likely waiting for this specimen?

Chemistry

200

The requisition contains an abbreviation you don't recognize.

Your friend says:

“I think it means a CBC. Just draw the lavender.”

What's the smart move?

Do not guess. Clarify the order/test with the appropriate clinical or laboratory personnel before collecting.

200

You're in the vein.

The tube is connected.

But...

Nothing.

The child hasn't moved.

What's one thing you should check before immediately removing the needle?

Check the tube/collection system and needle position for a mechanical or positioning issue.

300

A child is being investigated for haemolytic anaemia. The laboratory requests a specimen containing whole blood with an anticoagulant that preserves blood cells for analysis.

Which tube do you choose?

Lavender — EDTA

300

The patient needs:

  • RBS
  • FBC
  • DIC
  • ALT

What is the order of draw?

DIC (light blue) → ALT(green) → FBC (lavender) → RBS (gray)

300

A yellow SPS specimen arrives from the pediatric ward. 

Where is it going ?

Microbiology

300

You've already collected the blood and are walking away when the doctor calls:

“WAIT! Add a ferritin to that sample.”

The requisition hasn't been changed.

What's your move?

Verify that the additional test is formally ordered and confirm with the laboratory whether the existing specimen is suitable and has sufficient volume for the add-on.

300

You're collecting blood when a small bump suddenly appears around the venipuncture site.

The child says:

“It hurts!”

What's happening?

A hematoma may be forming due to blood leaking into the surrounding tissue.

400

What tubes contains thixotropic gel ?

Gold & Light Green

400

What comes 5th in the order of draw?

Lavender

400

A child has three specimens collected:

Light blue → investigating abnormal bleeding
Lavender → evaluating blood cell counts
Yellow SPS → investigating infection

Match them to their respective departments?

Light blue → Coagulation
Lavender → Hematology
Yellow SPS → Microbiology

400

You have two pediatric patients:

Patient A:
CBC + electrolytes

Patient B:
PT/INR + blood group and screen

You accidentally pick up Patient B's requisition while standing beside Patient A.

You notice only after you've already opened your tubes.

What is the FIRST thing you should do?

Stop and verify the correct patient and current orders before collecting anything.

400

The child suddenly becomes:

  • pale
  • clammy
  • nauseated
  • dizzy

The needle is still in place.

What's your priority?

Stop the procedure safely and manage the suspected vasovagal reaction according to protocol, prioritizing the child's safety.

500

Match the test to the tube color.

  • BMP
  • HDL
  • ETOH
  • Total Bilirubin
  • Copper
  • BMP - Gold
  • HDL - Red
  • ETOH - Gray
  • Total Bilirubin - Green
  • Copper - Royal Blue
500

Arrange the additives in order:

  • SST
  • Sodium Heparin
  • ACD
  • Potassium Oxalate
  • SPS

SPS/ACD → SST → Potassium Oxalate → Sodium Heparin

500

Where does a red/light gray tube go?

N/A (discard tube only)

500

You’re called to collect blood from a 7-year-old admitted with suspected bacterial endocarditis.

The requisition reads:

Patient: Malik Jordan
DOB: 12/04/2019
Tests: CBC, PT/INR, Blood Culture ×2
Priority: STAT
Collection time: 10:00 AM
Ordering physician: Dr. A. Singh

At the bedside, you verify the child's wristband:

Malik Jordan — DOB 12/04/2019 ✅

But then you notice:

  • The current time is 10:25 AM
  • The nurse tells you one blood culture was already collected at 10:05 AM
  • The requisition still says Blood Culture ×2
  • The physician verbally tells you: “Actually, forget the PT/INR—we only need the cultures and CBC.”
  • The requisition has not been amended

What is the ONE thing you should NOT do?

Do not independently alter the laboratory order based solely on the verbal instruction.

500

You've finally entered a difficult vein.

The blood starts flowing.

Suddenly the child jerks their arm.

Your needle is still in the vein.

Your partner says:

“Don't pull out! Just move the needle with the arm.”

What is wrong with that advice?

You should not manipulate the needle within the tissue to follow a moving limb/vein. The priority is to prevent needle-related injury and safely stop/manage the procedure.