Nurses have a number of responsibilities to perform to maintain their patients’ wellbeing, including collecting blood specimens. Blood culture collections are needed to make sure that patients do not have any foreign organisms in their bloodstream that can prevent them from remaining healthy. This relatively simple procedure must be executed correctly to ensure that the patients’ blood samples are not contaminated.
What are Blood Cultures?
Blood cultures are laboratory tests that consist of injecting blood into bottles that contain culture media to determine if microorganisms have entered the patient’s bloodstream. This laboratory test consists of gathering blood for one set of tests. Some blood goes into the anaerobic bottle and the remaining blood goes into the aerobic bottle.
Nurses must know the appropriate volume of blood to extract from each patient. For infants, nurses need a 3 ml syringe to place 0.5 – 1 ml in the aerobic bottle and 0.5 – 1 ml in the anaerobic bottle. Adults require a 20 ml syringe to place 10 ml in the aerobic bottle and 10 ml in the anaerobic bottle. Nurses must use a 20 ml syringe to place 2.5 -10 ml in the aerobic bottle and 2.5 -10 ml in the anaerobic bottle for infants.
It may not be possible to collect 20 ml of blood from some adults. In this case, nurses should take the blood collected and use it all in the aerobic bottle. Nurses should never use more than 10ml of blood in each bottle.
Steps for Drawing Blood Cultures
- Gather the materials needed to draw a blood culture. The materials include sterile gauze, zip lock specimen bags, tape, patient labels (self-adhesive), gloves, tourniquet, alcohol swabs, chlorhexidine swabs, blood culture bottles (2 bottles for each set), 2 needles (23 or 25 gauge for pediatrics and 22 gauge for adults), and 2 syringes ( 5 cc or pediatrics and 22 cc for adults).
- Wash hands for at least 15 seconds with soap and warm water. Use the patient’s arm band to identify the patient against the information in the patient’s chart. Explain the process to the patient and answer any questions that the patient has.
- Prep the cap of the culture bottles using alcohol pads. Clean the area using a circular motion. Make sure that the area is dry before proceeding.
- Use chlorhexidine to prepare the puncture site. Remove the applicator from the packaging.
- Hold the applicator with a gloved hand and point it downward, squeeze the wings very gently to release the solution.
- Scrub the area for 2 minutes if applying to wet skin or 30 seconds if applying to dry skin. Using a back and forth motion is best. After cleaning the site with chlorhexidine, do not wipe the area again.
- Don sterile gloves before moving to the next step. Use nonsterile gloves if it is not necessary to perform a physical examination before puncturing the site, or use sterile gloves if palpation is necessary before puncturing the site.
- Collect the correct amount of blood for each specimen. Use the following guidelines:
- Adults – 20 ml syringe – 10 ml (aerobic bottle) and 10 ml( anaerobic bottle)
- Pediatric – 20 ml syringe – 2.5 -10 ml (aerobic bottle) and 2.5 – 10 ml (anaerobic bottle)
- Infants – 3 ml syringe – 0.5 – 1 ml (aerobic bottle) and 0.5 – 1 ml ( anaerobic bottle)
9. Mix the blood in the bottles by gently rotating the broth and blood contained in the bottles.
10. Label the patient’s bottles with the self-adhesive labels. Also, write the collection site for each specimen on the label. Apply the laboratory requisition to the bottle. Make sure that the labels do not cover the bar code on each of the bottles.
11. Immediately send the blood cultures to the laboratory for testing.
12. Document in the medical records the collection site and the time and date in which the specimen was collected.
13. Obtain the second set in the same manner in which the previous set was collected. Make sure that different materials are uses and a different collection site is used as well.
14. Remove gloves after disposing of used materials.
Video on Blood Culture Collection Procedure
How to Prevent Blood Culture Contamination
To prevent blood culture contamination, nurses should clean the collection site prior to drawing blood to prevent contamination and false positives. Doctors have a hard time determining if the bacteria are a real infection or if they were caused by skin contamination.
Experienced nurses know the importance of proper blood culture collection. Contaminated blood culture collections can lead to an extended hospital stay or prolonged use of various antibiotics. Nurses must put the wellbeing of their patients first when collecting blood culture samples.