• Post last modified:December 31, 2022
  • Reading time:8 mins read

Blood collection and analysis is one of the most important diagnostic procedures available to clinicians within healthcare. Its data is relied upon in the clinical setting for the interpretation of pathological signs and symptoms.

Phlebotomy for Blood Collection

The surgical opening or puncture of a vein to withdraw blood or to introduce fluid is called phlebotomy. The person who performs phlebotomy is called a phlebotomist, doctor, nurse & medical laboratory scientist.

Requirements for Blood Collection

  1. Syringes and needles
  2. Tourniquet
  3. Specimen containers (or evacuated tube system) – plain and with various anticoagulants
  4. Request form
  5. 70% isopropanol swabs and cellulose pads
  6. Adhesive dressings
  7. Self-sealing plastic bags
  8. Rack to hold specimen upright during the process of filling
  9. A puncture-resistant disposal container should also be available
  • NEEDLES should not be too fine/ too large/ too long
  • Vary from large (16 G) to small (23 G)
  • For adults – 19 or 21 G suitable
  • For children- 23 G
  • Ideally should have a short shaft (15mm)
  • Butterfly needles- when blood has to be collected from a very small vein
  • Come in 21, 23, and 25 G

Blood can be collected from 3 different sources

  1. Capillary
  2. Artery
  3. Vein


Venipuncture involves puncturing with a needle and collecting blood in a syringe or evacuated tube. Venipuncture is a routine and common procedure done to collect venous blood directly from the vein.

It is performed using the antecubital fossa, a vein of the wrist, the dorsum of the hand or foot, or other accessible location.

The best site for blood collection is: Ante-cubital fossa

In order to do this safely, the phlebotomist must have a basic understanding of the following:

  • Anatomy
  • The criteria for choosing a vein
  • The device used
  • Skin preparation
  • Personal safety – infection control policy

Most common sites for Venipuncture – Blood collection

  1. Median cubital vein
  1. Dorsal Venous Network

Venous Puncture Technique for Blood Collection


  1. Verify computer-printed labels match requisitions
  2. Check patient identification band against labels and requisition forms
  3. Ask the patient for his/her demographics
  4. Position patient properly
  5. Assemble equipment and supplies
  6. Apply a tourniquet on the upper arm and ask to make a fist
  7. Select a suitable vein for puncture
  8. Put on gloves
  9. Cleanse the site
  10. Enter skin with needle at 30-degree angle/ < to arm with bevel up of the needle
  1. Follow the geography of the vein and insert the needle smooth
  2. Using a syringe, pull back on the barrel with a slow, even tension as blood flows into the syringe
  3. Release the tourniquet when blood begins to flow.
  4. Never withdraw the needle without releasing the tourniquet

Precautions in Blood Collection:

  • The area must be cleaned/appropriately sterilized.
  • The tourniquet should not be applied for a long time.
  • Blind attempts should not be made.
  • Once the needle is withdrawn pressure should be applied and maintained for 1-2 minutes, if not can cause ECCHYMOSES.


  • Recheck the patient’s details and make sure it corresponds to the information on the request form
  • Each submitted specimen must be labeled with the patient’s Demographics (written exactly as it appears on the Test Request Form) and the tests to be conducted
  • Patient demographics include – Patient name, sex, age, DOB, DOA, DOE, hospital number, room number, lab number, physician, and physician’s pharmacy code number
  • Use one Test Requisition form only
  • Label each specimen with the patient’s name, and time of specimen collection
  • Write the Total number of specimens submitted on the Test Requisition form Specimens should be sent in individual plastic bags/ set upright in a holder or rack, separated from the request form to prevent contamination in event of leaking
  • Without separating the needle from the syringe place both together with the swab and any dressings in a puncture-resistant container