Examinations & Procedures - Part 2

Blood Culture Collection Technique

Here are the detailed steps for collecting a blood sample for blood culture:

• Wash your hands thoroughly and put on gloves and other personal protective equipment if necessary.
• Select the appropriate site for venipuncture. The most common sites for venipuncture are the antecubital fossa (inner elbow) and the back of the hand. Choose a site that is free from any obvious infection or inflammation.
• Clean the site with an antiseptic solution, such as chlorhexidine or iodine. Allow the solution to dry completely before proceeding.
• Put on sterile gloves and prepare the blood culture bottles. Most blood culture systems come with two bottles: one for aerobic and one for anaerobic cultures. Label the bottles with the patient's name, date, and time of collection.
• Insert the needle into the vein at a 15 to 30-degree angle. Once you have successfully entered the vein, blood should start to flow into the collection tube.
• Collect the appropriate amount of blood for the culture bottles. The amount of blood needed will depend on the size of the culture bottle and the age of the patient. Generally, 10-20 mL of blood should be collected for each bottle.
• Withdraw the needle and apply pressure to the site with a sterile gauze pad. You may need to hold pressure for several minutes to prevent bleeding.
• Properly dispose of all used materials and transport the culture bottles to the laboratory as soon as possible.
• Document the date, time, and amount of blood collected, as well as any complications or patient reactions.
• Monitor the patient for any signs of infection or adverse reactions following the blood collection.

It's important to follow these steps carefully to ensure that the blood culture is accurate and reliable. Good luck!

Different bottles used for blood cultures

In the UK, the most commonly used bottles for blood cultures are BacT/ALERT® FA (aerobic) and BacT/ALERT® FN (anaerobic) bottles, which are part of the BacT/ALERT® blood culture system.

BacT/ALERT® FA (aerobic) bottles contain a special resin that absorbs antibiotics, making it possible to detect antibiotic-resistant bacteria. These bottles are designed to support the growth of aerobic bacteria, which require oxygen to grow.

BacT/ALERT® FN (anaerobic) bottles contain a reducing agent, which creates an anaerobic environment for the growth of anaerobic bacteria. These bottles are designed to support the growth of anaerobic bacteria, which do not require oxygen to grow.

Both types of bottles are used together to maximize the chances of detecting all types of bacteria that may be causing an infection. The bottles are usually labelled with the patient's details and a unique identification number, and then transported to the laboratory for analysis.

Blood culture bottles color codes

The BacT/ALERT® FA (aerobic) bottle in the UK is typically purple in color, while the BacT/ALERT® FN (anaerobic) bottle is typically green in color. However, it's important to note that the specific color coding may vary depending on the blood culture system used by the laboratory or hospital. It's always important to follow the manufacturer's instructions and any local protocols for handling and labeling blood culture bottles to ensure accurate and reliable results.

When to expect blood culture results

The time it takes to get the final results of blood cultures can vary depending on several factors, including the type of microorganisms that are being tested for, the sensitivity of the culture, and the laboratory's workload. In general, it can take anywhere from 1-7 days to get the final results of blood cultures.

However, preliminary results can often be available within 24-48 hours. These preliminary results can give doctors a general idea of what type of bacteria or other microorganisms are causing the infection, and can help guide initial treatment decisions while waiting for the final results.

It's important to note that some types of bacteria can grow more slowly than others, so in some cases, it may take longer than a week to get the final results of blood cultures. Additionally, in certain situations, such as when a patient has been receiving antibiotics prior to the blood culture being taken, it may take longer to obtain conclusive results or the results may be less reliable.