Healthcare and Medicine Reference
Step-by-step guide: blood culture
not touch the skin again after it has been cleaned (non-touch
Clean the tops of an anaerobic and aerobic blood culture
Give a full explanation to the patient in simple terms and
ensure they consent to the procedure. Prepare equipment
bottle using a chlorhexidine/alcohol wipe. Allow to dry fully
Collect at least 20 mL blood in a syringe, using a 21G (green)
needle or vacutainer system (Figure 5.8c,d).
If using a needle and syringe, be sure to use a clean needle
Collect culture bottles, phlebotomy equipment and antiseptic
stick (Figure 5.7).
Identify an accessible vein.
for each culture bottle and place at least 10 mL blood in each
Label fully with clinical details, antibiotics currently being
Ensure the skin over the vein is sterile by using an antiseptic (2%
chlorhexidine in 70% alcohol solution). Allow to dry and do
administered to the patient and the time and date of the sample.
Some organisations require the barcode attached to the culture
bottles to be removed and either placed in the patient notes
or attached to the request form. Check for local guidance.
Femoral venous access
This is used when alternative veins are unsuitable for phlebotomy,
such as if the upper limbs are not accessible, if infection is present
or if the patient simply has poor veins for venepuncture.
Anatomy of the femoral triangle
It is important to know the anatomy of the femoral triangle
when attempting a femoral stab. It is a space found in the groin,
demarcated medially by the adductor longus muscle edge
(apparent by fl exion, abduction and laterally rotation of the thigh),
laterally by sartorius and superiorly by the inguinal ligament
(this runs between the pubic tubercle and the anterior superior
iliac spine). The femoral artery, nerve and vein are all found within
the femoral triangle (Figure 5.9).
Sampling is obtained using a 21G needle and a 20-mL syringe.
Palpate for the femoral artery; the femoral vein lies medial to
Wipe the skin with an antiseptic wipe (2% chlorhexidine/70%
alcohol) and allow the skin to dry.
Insert the needle approximately 1 cm medial to the femoral
artery, and at 90° to the skin, withdrawing the plunger as you
advance the needle.
Figure 5.7 Equipment for taking cultures.
Figure 5.8 Step-by-step guide: blood cultures. (a) Removing the tops of culture bottles. (b) Cleaning the tops of blood culture bottles using 2% chlorhexidine
in 70% alcohol solution. (c) A butterfl y needle inserted into a vein. (d) A blood culture sample being taken.