NCMA Phlebotomy Procedures and Order of Draw 2 — Questions and Answers

Question 1: What is the correct order of draw when collecting multiple tubes during a single venipuncture?

Blood culture bottles → Yellow SPS → Light blue (sodium citrate) → Red/gold SST → Green (heparin) → Lavender (EDTA) → Gray (fluoride) (Correct answer)
Lavender → Red → Light blue → Gray → Green → Yellow
Gray → Lavender → Red → Light blue → Yellow → Green
Red → Light blue → Green → Lavender → Gray → Yellow → Blood culture

Correct answer: Blood culture bottles → Yellow SPS → Light blue (sodium citrate) → Red/gold SST → Green (heparin) → Lavender (EDTA) → Gray (fluoride)

CLSI-recommended order of draw prevents additive carryover between tubes: blood cultures first (sterile technique), then light blue (citrate, critical to fill exactly), then additives in sequence — SST, heparin, EDTA, fluoride.

The order of draw rationale: Blood cultures first (prevent contamination); Yellow SPS (before any additives contaminate); Light blue last among non-blood-culture tubes that need pristine coagulation testing (citrate ratio is critical — short-draw invalidates PT/PTT); SST/red (clot activators); Green (heparin); Lavender (EDTA — if drawn before heparin, can cause spurious hyperkalemia); Gray (fluoride/oxalate). The mnemonic 'Stop Light, Run Boys Right Go' or 'Boys Love Righteous Green Giants Looking Gray' helps recall the color sequence.

Question 2: What is the purpose of inverting blood collection tubes immediately after drawing?

To mix the blood with the tube's additive (anticoagulant or clot activator) to achieve the intended preservation or anticoagulation effect (Correct answer)
To prevent the tubes from breaking during transport
To make it easier to label the tubes
To separate serum from cells immediately

Correct answer: To mix the blood with the tube's additive (anticoagulant or clot activator) to achieve the intended preservation or anticoagulation effect

Inverting collection tubes gently (3–8 times depending on the additive) mixes blood with the additive — EDTA, heparin, sodium citrate, or clot activator — ensuring proper anticoagulation or activation and preventing clotting in anticoagulant tubes or incomplete clot formation in SST tubes.

Required inversions by tube type: Blood culture bottles (8–10 inversions), Sodium citrate/light blue (3–4), SST/gold (5), Red plain (5), Heparin/green (8–10), EDTA/lavender (8–10), Fluoride/gray (8–10). Under-inversion in EDTA tubes can cause microclots that clog hematology analyzers; under-inversion in sodium citrate tubes allows partial clotting that invalidates coagulation results. Over-vigorous shaking (not gentle inversion) can cause hemolysis. Tubes should be inverted by rolling from end to end, not shaken.

Question 3: Where is the antecubital fossa located, and why is it the preferred venipuncture site?

The inner surface of the elbow joint; preferred because it has large, accessible veins (cephalic, basilic, median cubital) with minimal underlying nerve and artery risk (Correct answer)
The back of the hand
The inner wrist near the radial pulse
The upper arm near the axilla

Correct answer: The inner surface of the elbow joint; preferred because it has large, accessible veins (cephalic, basilic, median cubital) with minimal underlying nerve and artery risk

The antecubital fossa (AC fossa) is the triangular area on the anterior (inner) surface of the elbow; it is the primary venipuncture site because the median cubital, cephalic, and basilic veins are superficial, large, and anchored, making them accessible and stable for needle insertion.

The median cubital vein (the preferred vein — most superficial, well-anchored, low nerve proximity) crosses the fossa diagonally. The cephalic vein runs along the thumb side (may be harder to stabilize); the basilic vein runs along the pinky side and is deeper with greater nerve and artery proximity — use with caution. If antecubital veins are inaccessible, the dorsal hand veins or forearm veins are alternatives. Medical assistants should never perform venipuncture in an arm with a dialysis fistula, on the mastectomy side of a breast cancer patient, or on an arm with an active IV infusion.

Question 4: What is the purpose of releasing the tourniquet before withdrawing the needle during venipuncture?

To restore normal blood flow and prevent hematoma formation and excessive bleeding at the puncture site upon needle removal (Correct answer)
To slow blood flow so the tube fills more slowly
To prevent the tube from overfilling
To maintain pressure while changing tubes

Correct answer: To restore normal blood flow and prevent hematoma formation and excessive bleeding at the puncture site upon needle removal

Releasing the tourniquet before withdrawing the needle restores normal venous pressure; removing the needle while the tourniquet is still applied causes increased venous back-pressure that promotes hematoma formation (blood leaking into surrounding tissue).

The tourniquet should ideally be released as soon as blood begins to flow — within 1 minute of application maximum — to prevent hemoconcentration (elevated cell counts, protein, and some analytes due to fluid shift out of capillaries under prolonged compression). After the last tube is filled, release the tourniquet BEFORE withdrawing the needle, place gauze gently over the site, then withdraw in one smooth motion. Applying pressure immediately after withdrawal (without bending the arm initially — let the patient straighten their arm and apply pressure for 3–5 minutes) minimizes hematoma formation.

Question 5: What is the maximum recommended time a tourniquet should remain applied during venipuncture?

No more than 1 minute (60 seconds) (Correct answer)
5–10 minutes to allow vein filling
30 seconds only
As long as needed until the vein is found

Correct answer: No more than 1 minute (60 seconds)

CLSI guidelines recommend tourniquet application not exceed 1 minute to prevent stasis and hemoconcentration, which falsely elevate protein, potassium, calcium, hemoglobin, and hematocrit levels.

Prolonged tourniquet application causes venous stasis, forcing fluid from capillaries into interstitial tissue. This hemoconcentration effect elevates: total protein, albumin, cholesterol, triglycerides, calcium, potassium, packed cell volume, hemoglobin, and RBC count. If the tourniquet must be reapplied (failed first attempt), wait 2 minutes before reapplying to allow the arm to return to normal. If a difficult draw requires extended tourniquet time, label specimens accordingly and alert the lab, as some results may need to be interpreted with this caveat.

Question 6: A medical assistant accidentally punctures a patient's brachial artery during a venipuncture attempt. What is the IMMEDIATE appropriate action?

Remove the needle immediately, apply firm continuous pressure for at least 5 minutes, and notify the provider (Correct answer)
Continue drawing if blood is flowing because it doesn't matter which vessel was accessed
Reinsert the needle next to the artery
Apply a bandage loosely without pressure and release the patient

Correct answer: Remove the needle immediately, apply firm continuous pressure for at least 5 minutes, and notify the provider

Arterial puncture is recognized by bright red, pulsatile blood flow; the needle must be removed immediately and firm, sustained pressure (5–10 minutes minimum) applied directly over the site to achieve hemostasis and prevent significant hematoma or compartment syndrome.

Indicators of accidental arterial puncture: blood is brighter red than venous blood, the tube fills rapidly with pulsatile flow, blood may spurt from the hub. Immediate management: withdraw the needle smoothly, apply firm (not light) continuous digital pressure for a minimum of 5 minutes (longer for patients on anticoagulants), check for cessation of bleeding before releasing, apply pressure bandage if appropriate. Document the incident, notify the provider, and monitor for compartment syndrome (pain, pressure, paresthesia in the forearm). The patient should be instructed not to lift heavy objects or flex the arm for 24 hours.

NCMA Phlebotomy Procedures and Order of Draw 2

What is the correct order of draw when collecting multiple tubes during a single venipuncture?