String Test in Paediatrics | childrensdoctor

Coiled Oesophageal String Test in Paediatrics

Monitoring eosinophilic oesophagitis without anaesthetic in paediatrics

The Coiled Oesophageal String Test (CEST) is a minimally invasive test that may help assess and monitor inflammation in the oesophagus in children with an established diagnosis of eosinophilic oesophagitis (EoE).

The purpose is to reduce the number of endoscopies needed in children and young people with EOE.

At present, Candover Clinic and Southampton Childrens Hospital are the only two places in the UK offering this test to children and young people.

Studies in Southampton show that the Coiled Oesophageal String Test gives results (ECP Levels) very similar to gastroscopy (Histology) in children. This graph shows a strong match between the two tests.

Understanding Eosinophilic Oesophagitis (EOE)

Eosinophilic oesophagitis is a long term condition where the oesophagus becomes inflamed because of allergic-type immune response involving cells called Eosinophils.

Symptoms vary with age and may include:

Difficulty swallowing
A feeling that food is getting stuck
Reflux type symptoms
Feeding problems in younger children

Foods are often a trigger.

This picture shows ring‑like markings in the food pipe (oesophagus) of a child. This is a typical and well‑recognised appearance seen in children with Eosinophilic Oesophagitis (EoE).

Why monitoring EOE can be difficult ?

Management often involves:

Removing certain foods from the diet
Changing or adjusting medicines
Slowly re-introducing foods over time

To see if treatment is working, current guidelines often recommend repeat endoscopies with biopsies. This can mean several anaesthetics each year, time away from school, and understandable worry for children and their families.

What does the Coiled Oesophageal String Test involve ?

A thin, specially designed coiled string is gently swallowed with water
The string is gently secured to the cheek
The string remains in place for around 30 minutes
The string is then carefully removed

During this time, the string collects proteins from the lining of the oesophagus.

Eli Rana chatting comfortably with Dr Afzal about his symptoms during his string test in the outpatient clinic. You can see the string taped to the side of the mouth.
In the UK, this test for children is only available at Candover Clinic and Southampton Children’s Hospital.

Who may be suitable for this test ?

The test may be suitable for children who:

are being checked for possible EoE
have known EoE and need monitoring over time
are able and comfortable swallowing the thin coiled string

At Candover Clinic, the youngest child to successfully have this test has been 6 years old. Children usually find it easier as they get older.

Each child is different and suitability is always decided on individual basis.

This photograph shows a swallowed string in a younger child. The child is very comfortable and has opened their mouth so Dr Afzal can take a photo to show the string in place. The string test is generally well tolerated by children.

Can families attend from outside Southampton ?

Simply Yes.

Families can attend Candover Clinic just for this test, while their child continues routine care with their own paediatric gastroenterologist. Children have travelled from outside the local area, and to date one child has even been seen (with a successful string test) from another country within the UK.
The string test results can be shared with your child's specialist to help and guide ongoing management. The result is simply a number which is ECP level in the oesophagus

What is the child's experience like ?

No anaesthetic is needed
The test is done as an outpatient clinic visit
Most children can return to school the same day
There is no pressure to go ahead if a child feels uncomfortable

What is the cost ?

The aim is to offer this test at a much lower cost than a children’s endoscopy performed under a general anaesthetic, and to avoid hospital admission where possible.

The cost of one test is £200.

The team has worked hard to keep the cost low so that the string test is easily accessible for children who may need it.