Collection of Blood Specimen

Blood specimen collection is performed to obtain blood for medical laboratory testing. Blood can be collected from three different sources- venous blood, arterial blood and capillary blood. Venous blood is preferred for hematological investigations but capillary blood can be nearly as accurate if a free flow of blood is obtained and there is no dilution error due to tissue fluids.

Standard precautions:

• All patients and laboratory specimens are treated an infectious and handled according to the “Standard Precautions”. This includes:-
• Personal Protective Equipment's (PPE) like gloves, mask, close shoe, goggles, etc should be used.
• Perform hand hygiene
• Follow the waste management practices: Leak-proof and puncture resistant sharp container should be used. Two leak-proof infectious waste bags, one for disposable materials (destruction) one for reusable materials (disinfection).
• Fill out patient documentation, necessary laboratory forms and epidemiological questionnaire.

 Sites of blood sampling

1.  Venous Blood Collection:

Venipuncture is the most common way to collect blood from adult patients. Venipuncture method is used for collection of large amount of blood from the vein. The commonly used veins are brachial vein, cephalic vein and median cubital  vein in adult and umbilical vein & scalp vein in infants.

Blood is most commonly obtained from the superficial veins of the upper limb, generally from median cubital vein because it is closer to the skin and doesn’t have many nerves positioned close by. This reduces pain of the patient. Venipuncture is the most common way to collect blood in medical field, usually performed because most of the routine tests are performed on venous blood.

Material required for vein puncture:

• A single use syringe with needle
• Tourniquet (non-latex)
• Doctors alcohol peps or Beta dine (povidone-iodine) swab
• Suitable blood collection tube
• Gauze pads or cotton-wool ball
• Sterile band aid/surgical tape/paper adhesive tape

Procedure of venous blood collection:

• Identify the patient. Introduce yourself to the patient and check the laboratory form matches the patient’s identity.
• Make patient comfortable in a supine position. Position the patient in a chair, or sitting or lying on a bed.
• Label the blood collection tube with the patient details.
• Select the site preferably at the bend of the elbow.
• Apply tourniquet around the arm 3-4 inches above veinpunture site and hold ends up.
• Ask the patient to form a fist so that the veins are more prominent.
• After finding the vein, disinfect the area where you will put the needle with doctor’s alcohol.
• Position the needle in the direction of the vein parallel to it. Needle should be at 15-30 degree angle. Enter the vein in smooth quick motion.
• The piston of the syringe is move backward; hence blood enters in the syringe.
• After collection of require amount of blood, the tourniquet is released. A cotton ball is held firmly over the puncture site and the needle is gently withdrawn.
• Blood is transferred to the appropriate vial or blood collection tube and mixed the blood with anticoagulant carefully.
• Told the patient to wait for few minutes, when blood flowing stopped then cover the puncture area by using banded.
• Dispose used cotton, syringe into a non-penetrable containers (Blue basket).

2.  Arterial Blood Collection:

Arterial Blood can be obtained from a superficial artery such as redial and brachial artery. Arterial Blood is used in the identification of metabolic, respiratory, and mixed acid-base disorders, where CO2 levels require understanding or monitoring. While generally safe, the procedure can be upsetting and painful for the patient. There is also an increased risk of bleeding complications in patients with coagulopathy.

Material required for arterial blood collection:

• Needles (20, 23 and 25 gauge, of different lengths) 
• Single-use syringe with a needle cover
• Doctors alcohol peps or Beta dine (povidone-iodine) swab
• Suitable blood collection tube
• Gauze pads or cotton-wool ball
• Sterile band aid/surgical tape/paper adhesive tape
• A container with crushed ice

Procedure of arterial blood collection:

• Identify the patient. Introduce yourself to the patient and check the laboratory form matches the patient’s identity.
• Place the patient on their back, lying flat.
• Position the patient’s arm with the wrist extended and locates the radial artery with your index and middle finger.
• Let the patient know you are to proceed and to expect a sharp scratch.
• Disinfect the area where you will put the needle with doctor’s alcohol.
• Insert the needle at 45 degree angle to the skin at the point of maximum pulsation of radial artery.
• Advance the needle until arterial blood flushed into the syringe. The arterial pressure will cause the blood to fill the syringe.
• Remove the needle/syringe placing the needle into the bung. Press firmly over the puncture site with the gauze to stop bleeding. Remain pressed for 5 minutes.
• Activate the mechanisms of a safety needle to cover the needle before placing it in the ice cup
• Expel air bubbles, cap the syringe and roll the specimen between the hands to gently mix it. Cap the syringe to prevent contact between the arterial blood sample and the air, and to prevent leaking during transport to the laboratory.
• Label the sample syringe.
• Dispose appropriately of all used material and personal protective equipment.

3. Finger stick sampling:

Finger stick is a procedure in which small quantity of capillary blood is collected by pricking the finger with a lancet, usually from the end of a finger. It is done very quickly and requires very little in the way of preparation; therefore, reducing concern and anxiety in patients, particularly in children and nervous adults. Tests commonly conducted on the capillary blood collected are glucose levels, mononucleosis, hemoglobin levels, CBC, prothrombin time.

Material required for finger stick sampling:

• Latex Gloves
• 70%  isopropyl alcohol pads
• 2 X 2 gauze pads
• BD Microtainer Contact-Activated Lancet
• Sterile band aid/surgical tape/paper adhesive tape

Procedure of finger stick sampling:

• Be friendly with your patient. Patient cooperation is essential for successful results.
• Turn patients hand upward. Massage patients hand and lower part of finger to increase blood flow.
• Select site off to the side of the palm-side surface of the 2nd or 3rd finger. Avoid using thumbs, index fingers, or fingertips, which are more sensitive to pain.
• Cleanse puncture site with alcohol pad, dry with cotton ball or gauze and allow the area to dry.
• Hold the finger and firmly place a new sterile lancet off-center on the fingertip.
• Keep the figure in downward position and gently message it to maintain blood flow. Hold the microtainer at an angle of 30 degree below the collection site. Fill the micritainer to 350-500μL level.
• Cap  the microtainer and gently invert 10 times to prevent blood clotting.
• Apply a sterile band aid over the puncture site.