top of page

Blood samples

Obtaining a venous blood sample for analytical purposes

Collection of a venous blood sample from an uncannulated vein.


To obtain a sufficient amount of blood for the requested analytical determinations.


– Vessel. – Compressor. – Sharps container.


– Sterile gauze. – Disposable gloves. – Antiseptic solution. – Necessary tubes according to the request for analysis. – Identification labels. – Syringe method: 1 syringe of 5-10-20 ml and 1 intravenous needle. – Vacuum system method: 1 sterile double bevel needle and 1 needle holder. – Analytical request form. – Nursing records.


– Perform hand washing. – Check the analytical determinations requested to see the amount of blood needed according to the tubes. – Identify the tubes with the patient’s data. – Prepare the material. – Check the necessary conditions before blood sampling, according to laboratory standards (fasting, maximum and minimum drug peaks). – Preserve the patient’s privacy. – Verify the correct identification of the patient. – Inform the patient of the procedure. – Ask the patient to cooperate and to remain still during the venipuncture.

– Place the patient in the supine position with the arm in hyperextension. – Select the vein for venipuncture taking into account the amount of blood needed, patient comfort, age and condition of the veins. – Disinfect the area with antiseptic with circular movements, starting at the point of venipuncture and moving outwards. – Allow the skin to dry. – Place the compressor about 10-15 cm above the venipuncture site. – Put on sterile gloves. – Syringe method: Place the intravenous needle in the syringe.  2. Clamp the vein with the thumb. 3. Insert the needle with an inclination of 20-30º in the direction of venous blood return. 4. Observe for venous return in the needle. 5. Stabilize the syringe and needle with the non-dominant hand and pull the plunger with the dominant hand to draw the necessary blood. 6. Aspirate gently to avoid hemolysis and collapse of the veins. – Vacuum system method: 1. Place the needle in the vacuum holder. 2. Fit tubing into the holder without puncturing the tubing. 3. Insert needle into the vein at an angle of 20-30º. 4. Stabilize the needle and adapter with one hand, with the thumb on the bottom of the tube and the index and middle fingers on the flaps of the adapter. Pre- sionate with the thumb and index finger to puncture the tube. 5. Check that blood flows through the tube. 6. Fill the necessary tubes. 7. Remove the last tube from the adapter. – Remove the compressor and needle. – Press on the puncture site until bleeding stops. – Discard needle and sharps in the container, according to waste segregation criteria. – Place the patient in a comfortable position. – Collect the material. – Remove gloves. – Wash hands. – Send the samples to the laboratory with the laboratory form. – Record in the nursing documentation: procedure, reason, date and time, incidences and patient’s response.

– Observations: – The use of biosafety materials is recommended. – Aseptic technique. – Fill the tubes with the necessary amount of blood: first the tubes with coagulable samples and then the tubes with anticoagulant until all the vacuum is consumed. Once filled, invert the tubes several times so that the blood and anticoagulant mix. – If the patient is under fluid therapy, it is preferable to choose the opposite arm. – Do not puncture arteriovenous fistulas or the arms of women with mastectomies because they have compromised venous return. – If the patient is anticoagulated, increase the pressure time.[/et_pb_text][/et_pb_column][/et_pb_row][/et_pb_section]

3 views0 comments


bottom of page