6. Venous blood collection clinical laboratory investigation – basic procedures and sources of errors

Question 1

What Must You Do to AVOID Problems with Hemo-Concentration + Dilution, in the Phlebotomy Procedure?

{PPT}

Answer 1

Patient Seated for 15-20 Minutes

Before Blood is Drawn

Question 2

How Should the Tourniquet be applied, in the Phlebotomy Procedure?

{PPT}

Answer 2

Enough to RESTRICT Venous Flow

NOT TIGHT to OCCLUDE Arterial Flow

Question 3

What % Alcohol Must be Used, When Cleaning the Venipuncture Site, in the Phlebotomy Procedure?

{PPT}

Answer 3

70% Alcohol

Question 4

How do you End the Phlebotomy Procedure?

{PPT}

Answer 4

RELEASE the Tourniquet = Blood BEGINS to Flow

Withdraw Needle ALONG WITH the Tourniquet

Question 5

What is the Order of Drawing Blood?

{PPT}

Answer 5

1) Haemoculture
2) Serum
2) Plasma = For Haemostasis
3) ESR + Heavy Metals
4) Whole Blood = For Haematology Test

Question 6

How Must You Place the Blood Sample in the Tube?

Answer 6

Gently Mix

Invert Tube with Anticoagulant

DO NOT Shake the tube!

Question 7

What are the Common Error BEFORE Venous Puncture?

Answer 7

Misidentification of the Patient

Patient NOT PROPERLY Prepared = WITHOUT 12hr Starvation

Change in Body Position BEFORE Procedure

Question 8

What are the Common Error DURING Venous Puncture?

Answer 8

1. Small Needles
2. Tourniquet being left on the arm for MORE THAN 1 Minute
3. Venipuncture in Improper Vein Site
4. Tapping on Vein
5. Pumping with Fingers, while Tourniquet is Applied

Question 9

1| What does Small Needles Lead to?

Answer 9

Haemolysis

Question 10

2| What Happens If You Leave the Tourniquet on for MORE than 1 Minute?

and What does this Influence?

Answer 10

Local Stasis

Haemoconcentration

Influencing Results for

• Albumin
• K+
• N.O of Erythrocytes
• HCT
• HGB
• WBC
• PLT

Question 11

3| What does a Venipuncture at an Improper Vein Site Lead to?

Answer 11

Haematoma

Question 12

4| What does Tapping on the Vein Lead to?

Answer 12

Haemolysis = Rupturing of RBCs

Activation of Coagulation Factors

Question 13

5| What does Pumping with Fingers, while Tourniquet is Applied, Lead to?

Answer 13

Local Acidosis

Haemolysis

INCREASING K+ and Lactate Levels by 20%

Question 14

What are the Common Error AFTER Venous Puncture?

Answer 14

NOT Loosening the Tourniquet, AFTER entering the Vein + drawing the blood

Wrong Tubes / Anticoagulant

Wrong Order of Evacuated Collection Tubes

Short Draw = WRONG Blood : Coagulant Ratio

Mislabelling of Specimen

Exposure to Light / Extreme Temp

Improperly Timed Specimens / Delayed Delivery

Question 15

What is Lipemia?

{PPT}

Answer 15

Serum Appears Milky or Turbid

DUE to Lipids = Improper Fasting (NOT 12hr Starvation)

Question 16

What does Jaundice Serum Look like?

{PPT}

Answer 16

Aka Icteric Serum

Appears Yellow = DUE to HIGH Bilirubin

Question 17

Which of the following procedures is WRONG?

{MCQ}

Answer 17

Tapping and Massaging the Vein