Blood Specimen Collection

Blood Specimen Collection is an important process in the clinical laboratory to collect biological samples for testing purposes, which gives valuable information about patients’ state of health. Blood specimens too form part and parcel of this process which need certain mode of collection, handing and processing. The venipuncture is the most used technique and for the Vacutainer is an effective method of taking blood samples. Both helps in achieving the correct measurements with less discomfort to the patients. The Vacutainer system means that blood can be collected directly into tubes that are specially equipped with a vacuum so that there will be no need for changing tubes which will reduce contamination and also make the process faster than adopting any other method. The following steps are taken so that there will be accurate result and little or no discomfort on the side of the patient.

Blood is one of the specimens which are most often taken for analysis in medical practice. 

• Venous Blood: Drawn from a vein usually from the subject’s arm for instance by use of a vacutainer system. Common for tasks including, Complete blood count, electrolytes, liver function tests and kidney function tests. 
• Arterial Blood: Obtained from an artery particularly for arterials blood gases to determine concentration of oxygen, carbon dioxide and the PH. 
• Capillary Blood: Usually, it is taken through fingerstick or heel stick particularly in cases where glucose test is required or in infants.
• Serum: The serum includes the remaining liquid after the blood has clotted and is utilised in numerical biochemical tests.
• Plasma: The fluid part of the blood with anticoagulants which is utilized for coagulation tests and other examinations.

Procedure Guidelines for Blood Collection

• Infection Control: Avoid using your bare hand to touch the patient and ensure you use gloves, maintain sterile ways to avoid getting an infection. 
• Patient Comfort: Comfort patients during the process to reduce the stress levels as well as pain felt by the patients. 
• Emergency Response: At the end of the procedure control any complication that might arise such as fainting or excessive bleeding. 
• Avoid Direct Sunlight: Some analytes should not be exposed to direct sunlight so the specimens must be stored away from such conditions. 
• Avoid Excessive Heat: It is advisable not to expose specimens to high temperatures since it poses a risk towards the sample. 
• Transfer to Vials: Option one – a syringe method: Fill the syringe with about 3 ml of the solution and injecting it into the vein of the patient while Option two – the vacutainer method: The vacutainer tube is fixed on the vein of the patient and about 3 mls of the solution is drawn into the tube. 
• Inversion: BWA lightly tumble the carter vial several a few time in order to ensure that the blood and the anticoagulant/additive, if used are in equal proportion.  
• Minimize Air Bubbles: This is very important to minimize the interference of air bubbles in the result of the test that has to be done. 
• Overfilling: Make sure that they do not over fill the vial so as to prevent spillages and mixing of the compound. 
• Sterility: Ensure standard precaution measures in the course of the procedure. 
• Documentation: Make sure that the collection details are clear in order to compare to the patient’s data and the necessary tests.  
• Nor is there shown how a blood specimen can be collected in a safe manner from a jealously guarded human patient.

A Step-by-Step Guide to Collecting a Blood Specimen 

Phlebotomy or drawing a blood specimen undergoes a procedure with different steps to guarantee specificity and security. Here's a detailed guide on how to do it:Here's a detailed guide on how to do it:

1. Preparation and Safety Measures 

The first and foremost step in the process of blood collection is that one has to make sure that the environment and all the accessories are ready and that all the necessary precautions are taken.

1.1. Hand Hygiene

Wear sterile gloves and wash your hands with soap and water or use alcohol based hand rub before and after the procedure. 

1.2. Prepare Equipments 

Before starting the procedure, ensure that you have all necessary materials:

• Needles (appropriate size, typically 21G or 22G): Choose the right gauge, that is normally a butterfly needle or a standard venipuncture needle for your task. 
• Syringe or Vacutainer system: The reason as to why blood is taken involves the type of blood test that has to be done. 
• Vacutainer holder: A vacutainer system is a holder of the needle made of the plastic and it holds the vial. 
• Blood collection tubes: The test kit is provided with patient information pre-printed on it, and the test specific additives are also available which can be of different colors for different tests, for instance, red-top, blue-top and purple-top. 
• Tourniquet: To facilitate clearer see through of veins and to clean the puncture site and disinfect it, it is necessary to make them clear. 
• Alcohol swabs: The purpose of this text is to clean the wound site and apply pressure on the area where the needle has been withdrawn.
• Gauze: The text instructs the use of pressure after needle withdrawal.
• Bandage: The puncture site needs to be covered post-procedure, post-procedure, and post-procedure.
• Gloves: This is primarily intended for personal protection.
• Sharps container for proper needle disposal
• Patient labels and test requisition form

1.3. Patient Identification

• Start by asking the patient full name and date of birth to ensure Identification of the patient is correct. 
• Confirm patient’s identity by requesting his or her full name and date of birth and comparing this information with that in the test requisition form. 
• Talk to the patient and let him her know what is going to happen and how they should feel each step of the way. 
• The patient should be well positioned comfortably seated with his or her arm out stretched and relaxed.

 2. Apply Tourniquet

• Place the tourniquet three to four inches above the level where puncture is to be made to make veins prominent. 
• Put the tourniquet around the upper arm increase the size of the veins. 
• Position it 3-4 inches above the venipuncture site which is in most cases at the antecubital fossa of the arm. 
• Squeeze in order to make the veins stand out but not enough to pinch the skin or hinder blood flow in arteries.
• Tell the patient to tighten his or her hand to make the veins more clearly visible but should not close the hand tightly because it will result in hemoconcentration.

 3. Select the Venipuncture Site

• Some of the grades include median cubital vein at the elbow or cephalic vein at the extent limb of the arm. 
• Feel for a vein in the arm, one that is hard and bouncy as opposed to hard and scaly. 
• One should not use thumb since it is misleading most of the time. 
• The most common being the median cubital vein located at the antecubital fossa but other veins such as the cephalic or the basilic veins may be used as well. The most common veins used are:
• The median cubital vein is the most preferred site for blood sampling among the four veins.

1. Cephalic vein
2. Basilic vein

 4. Procedure for Venipuncture Cleaning

• Wipe the surface at the spot where the needle is to be inserted with an alcohol swab, to disinfect it. 
• Usually, clean puncture site with alcohol swab or apply antiseptic wipe on the area. 
• Work from the inside –out, beginning at the middle of the site. 
• To control contamination or irritation let the glasses air dry for 30 seconds. 
• Pat skin dry to reduce risk of small specimens lodging into mainland skin and diluting sample: mainland skin must not dry for at 30 seconds at most. 
• I clean the area in and around the puncture site with an alcohol swab and wait for the area to dry.

5. Perform Venipuncture

• Wear gloves for safety and hygiene.
• Insert needle smoothly into vein in a single motion.
• Hold needle bevel-up at a 15-30 degree angle to the skin.
• Gently advance needle until slight resistance indicates vein entry.
• Collect blood using a needle and syringe or a vacutainer system.

If using the Vacutainer system

• Attach the vacutainer needle to the needle holder, allowing blood to flow directly into the vial. Gently advance the needle until a slight "pop" or resistance is felt, indicating the vein has been entered. The blood will automatically flow into the tube due to vacuum pressure. The appropriate vial should be attached to the needle holder, allowing blood to flow directly into the vial. Secure the needle tightly and remove the cap before insertion.

If using a syringe

• Syringe plunger is used to draw blood by pulling the plunger back and suck into the syringe to suck in a measured amount of blood. It is then connected to the needle holder ready to flow as soon as the vial is filled up to the required level. When collecting blood, the needle of the syringe is so gently inserted into the vial, and the blood is pumped gently out. Overfilling should not be done and should not be shaken vigorously as this may lead to formation of air bubbles and /or hemolysis which may distort results.

6. Collect the Blood Specimen

• Open and label the vial.
• Follow the correct order of draw if multiple vials are used.
• Hold the vial steady to prevent contamination.
• Collect the correct volume of blood for required tests.
• Follow the specific order of draw to avoid cross-contamination.
• Follow the recommended order to prevent cross-contamination.

• Blood culture bottles or tubes (yellow)
• Coagulation tube (light blue)
• Serum tubes (red or gold)
• Heparin tube (green)
• EDTA tube (lavender)
• Glycolytic inhibitor tube (gray)
• This will require to fill each of the tubes upto the mark but not passing or even going below the mark. Invert the tubes 5-10 times as a way of making the blood with any additives such as the anticoagulants. This made sure that there will be a good mixture of the blood with the required supplements.

If Using Syringe Method

• Withdraw the needle from the patient, replace needle and syringe onto the vial and then you squeeze the plunger to pull blood into the syringe. If using a vacutainer then screw the correct tube to the needle and fill the tube with blood.

 If using the Vacutainer system

• The collection of blood entails fixing a sterile needle on a vein, placing the first Vacutainer tube from the back end of the needle and then placing the tube on the needle holder. In this case, as a result of evaporation related to vacuum pressure inside the tube blood gets pulled into the vial. Measure in the tube needs to be filled completely and the tube has to be fastened securely without spilling. Air bubbles must also be kept to the minimum since they will interfere with some of the tests. If, however, several tubes are required, then once a tube is filled, it has to be replaced by the next one and all of the tubes filled up to the mark indicated. If using EDTA, heparin, or citrate tubes gently turn each tube 5-10 times to mix additives with the blood, if needed. 

7. Filling the Tubes

• If multiple tubes are needed, follow the correct order of draw to prevent contamination between additives:
1. Blood culture bottles or tubes (yellow)
2. Coagulation tube (light blue)
3. Serum tubes (red or gold)
4. Heparin tube (green)
5. EDTA tube (lavender)
6. Glycolytic inhibitor tube (gray)
• Allow each tube to fill to its indicated mark (never overfill or underfill). Once filled, gently invert tubes 5-10 times to mix the blood with any additives (e.g., anticoagulants).

8. Release the Tourniquet

• Collect required blood volume.
• Release tourniquet to restore circulation.
• Ask patient to relax fist.

9. Remove the Needle

• Place gauze pad over puncture site. Carefully withdraw needle and apply pressure.
• Bandage site.
• Continue pressure for 2-3 minutes.
• Continue pressure to stop bleeding.
• Repeat process to prevent bruising or bleeding.

10. Apply Bandage

• Apply adhesive bandage to puncture site.
• Protect and prevent further bleeding.
• Apply bandage after bleeding has stopped.

11. Dispose of Needle and Sharps

• Dispose of used needle and sharp items immediately.
• Safely dispose of needle and Vacutainer holder in a sharps container.
• Dispose of needle and sharp objects in designated containers.

12. Label the Specimen 

• Proper identification of tubes, blood samples, vials with full name, identification number, date of birth as well as the time of collection. 
• Have to confirm information, especial in number before the procedures start.

 13. Handle and transport the specimen. 

• It includes storing and transporting of specimens based on individual test profiles, handling of a specimens as per laboratory norm and procedures, and gently rocking blood collection tubes containing anticoagulant and blood to avoid clotting and ensure sample preservation.  
• There is the need to ensure the specimen has been timely delivered to the laboratory given that the specimen may degrade. Samples of blood should be collected and next sent to the laboratory with special reference to the recommended transportation in order to reduce chances of degradation. This acts as makes sure that the specimen do not delay and are safely preserved. 

 14. Document the Procedure 

• The details like the time, site, and the reaction of the patient and the time of the draw, the volume of blood collected and complications or reactions that occurred should be recorded in the patients’ records.

15. Storage Conditions

Vials should also be stored according to different tests’ requirements for the conditions of room temperature, refrigeration and freezing; accordingly, vials should also be grouped according to the conditions of room temperature, refrigeration and freezing.

• Room Temperature: The majority of blood samples can be kept in store at the temperature which is range between 20 and 25 degrees centigrade or 68-77 degrees Fahrenheit for a few hours till the test is carried out. 
• Refrigeration: Samples not requiring testing at the time should be stored at temperatures of 2 - 8 o C / 36 – 46 o F. 
• Freezing: In specimen storage or for special tests, they may have to be stored at -20°C(-4°F) or below. 

 

Conclusion 

Blood specimen is an important pre-requisite in undertaking medical tests known to involve blood sample, urine sample, saliva and many others. They include putting a tourniquet around the vein, preparation of the vein, puncture of vein for blood sample and removal of the needle. The collected blood is consequently aliquoted into appropriate sized vials by using a proper needle and syringe or vacutainer system. Some of the steps include; vial labeling, blood sample collection, positioning of the vein and proper choice of the vein. The vial is capped securely to minimize on the chances of leakage after the procedure is done. Another factor is the method of sample storage as the conditions affect the sample quality in order to get accurate test results. Hand hygiene is paramount and the vacutainer system is the best method which is standard in blood collection. The above steps minimize mistakes, infection, or distress to the patient hence having quality blood sample for required diagnostic test.