Chapter 7. Collection of specimens
Background
When a midwife is requested to take a specimen from a mother and baby, it is usually when there is suspicion of infection, or as part of screening when women or babies have identified risk factors. It involves collecting material from the suspected source of the infection such as urine, or wound exudate collected on a swab. Culturing and identifying the micro-organism obtained by the swab or specimen allows for specific antibiotics to be prescribed for that particular micro-organism in order to treat and eradicate the infection (Johnson & Taylor 2006).
Neonatal sepsis
Neonatal infection has been described as infection which occurs during the first four weeks of life (HPA 2005). It may be superficial, such as conjunctivitis or skin infections, or deep infection, such as pneumonia or meningitis (HPA 2005). Neonatal infection is further subdivided into early onset infection, which occurs in the first 48 hours of life and is usually caused by infection ascending from the maternal genital tract, or late onset, which occurs after the first 48 hours of life where organisms may be acquired from the external environment (HPA 2005).
Risk factors to the development of neonatal sepsis include: congenital abnormalities; low birth weight; pre-term birth; prolonged rupture of the membranes; maternal fever; prolonged labour or birth trauma; respiratory distress syndrome; pre-eclampsia; babies of mothers who have previously had a baby affected by GBS.
Obtaining specimens
Swabs
Swabs should ideally be taken before antibiotic therapy has been commenced (Mallik et al 2004). There are specific swabs for particular purposes depending on the organism to be tested for, although for the majority of cases a dry swab plunged and sealed into a normal transport medium will suffice (Johnson & Taylor 2006). The dry swab should be fully coated in the fluid sampled by gentle rotation at the site of collection. All swabs should be clearly labelled with the site of sampling. So if it is the umbilicus, this should be stated, and if it is the ear or eye, which ear or eye should also be clearly stated. Samples should also be labelled with the time of collection as well as the date and patient identification.
Vaginal swabs
The kinds of specimens that might be taken include high vaginal and low vaginal swabs, to test for Group B Streptococcus or for sexually transmitted infections. Group B Streptococcus has been found to be the most frequent cause of early onset infection in newborn babies (RCOG 2003). Therefore, in women classed to be at risk of GBS, diagnosis can allow doctors to attempt to prevent the infection of the newborn.
Swabs are taken from the vagina (see procedure in Box 7.1 below), either a high vaginal swab taken from the top of the vagina using a speculum (McKay-Moffat & Lee 2006), or a low vaginal swab taken from inside the introitus. Low vaginal swabs may detect the presence of infection in lochia, suggestive of intrauterine infection, for example.
Box 7.1
Procedure for specimen collection
■ Check the client’s case notes and medical record, in consultation with the client
Rationale To ascertain the type of specimen to be collected and why it is required. The client should be aware of the plan to undertake the test and what the result might mean
■ Explain the nature of the specimen and the procedure for its collection, and gain verbal consent from the client
Rationale The client should give clear consent to any procedure which involves you touching the client or obtaining a specimen from them. The client may take the specimen themselves and give it to you, which suggests they consent to the test. However, they should also understand what will happen to the specimen, how long the results are likely to take, and how they will find out about the results
■ Prepare equipment necessary to carry out the specimen collection: check the right container or medium for each specimen
Rationale To ensure ease of carrying out the procedure, and that the appropriate specimen is collected from the right part of the body utilizing the right container or transport medium
■ Label the containers/swabs with the patient information according to hospital policy
Rationale To ensure the right tests are carried out for the right patient, and to minimize the potential distress of having to repeat the specimen collection
■ Wash hands
Rationale To avoid contamination of specimen container; to carry out clean procedure
■ Apply non-sterile gloves
Rationale To protect practitioner from infection risk presented by body fluids
■ Collect specimen (see procedure for individual specimen collection below)
Rationale To ensure adequate specimen sent for analysis
■ Remove gloves and wash hands
Rationale To reduce the risk of cross infection and/or contamination
■ Send specimen in appropriate, labelled envelope to correct department
Rationale To ensure speedy delivery of the specimen to the laboratory. To ensure correct analysis is carried out for the individual patient
■ Document the procedure in the maternity notes/medical notes and plan of care
Rationale To ensure good information sharing with other professionals; to keep a clear record of all care; to highlight in the plan of care the need to follow up results.
Eye, ear, nasal and umbilical swabs
Swabs taken from these areas are used to detect colonization by micro-organisms that can cause infection and illness, either in mother (except for umbilical swabs) or baby.
Eye swab: the woman should be sitting up with the head supported; the baby should be held with its head supported, preferably by its mother or father. The lower eyelid is pulled down very gently, and the swab held parallel to the cornea to avoid injury (especially if the baby moves), and then moved gently against the conjunctiva of the lower eyelid (Johnson & Taylor 2006). The swab is then placed in the transport medium, sealed, labelled and sent via the appropriate route to the laboratory. Separate swabs should be taken from each eye.
Ear swab: seat the woman with her head tilted to the unaffected side; the baby should be firmly held with the unaffected ear against its parent’s chest, with the head tilting upwards slightly (Johnson & Taylor 2006). The swab is placed gently into the outer ear and rotated. Some sources recommend straightening the external canal by gently pulling the pinna upwards and backwards, but care should be taken not to insert the swab too deeply in this case as there is a risk of damage to the eardrum. As with the eye, if both ears are to be swabbed, separate swabs should be taken from each ear.
Nose swab: seat the woman with her head tilted back; the baby can be held or laid supine. The swab should be moistened with sterile water, then inserted gently into the nose, directed towards the front of the nose and rotated (Johnson & Taylor 2006).
Throat swab: ask the woman to tilt her head backwards and stick out her tongue. Wearing gloves, depress the middle of the tongue with a disposable tongue depressor (like a large lollipop stick) and rub the tip of the dry swab around the tonsil area, taking care not to touch the lips or teeth (Timby 2005). Avoid the back of the throat as touching this stimulates the gag reflex and may make her vomit.
Umbilical swab: the baby should be held or positioned to provide access to the umbilicus, and clothing/nappy should be removed. As with other swabs, the tip should be rotated around the surface of the umbilicus and then the specimen labelled with the baby’s information before being sent to the laboratory.
Wound swabs
Wound infection can prevent or slow down wound healing. The kinds of wounds midwives will see include vaginal, vulval and perineal lacerations or tears, which may have been sutured, and postoperative wounds, typically from a caesarean section. Wound sampling can provide key biological information which, if interpreted in conjunction with the overall clinical picture, can inform optimal care management and planning (Gilchrist 2000). Midwives will generally undertake superficial wound sampling, from wounds where there are obvious signs of infection or where drains have been removed.
Placental specimens
Placental swabs
The swab should be moved across the surface of the placenta in a zigzag direction (Johnson & Taylor 2006). The swab should be labelled appropriately and the placenta disposed of in the usual manner.
Placental histology
Histological examination of the placenta may be indicated in certain clinical situations, requiring that the whole placenta or a portion of it be sent to the laboratory. This might be the case following a multiple birth, for example, to determine whether the infants are monozygous or dizygous or if there are any anomalies. It might also be necessary in preterm births, or following a stillbirth (Medforth et al 2006). In some cases it might also be a requirement to send the placenta itself where infection is suspected. Other indications include the birth of infants with congenital abnormalities, a two-vessel umbilical cord, and placental abruption.
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