If your child needs tests, it is natural to want to know what they involve and why they are necessary. You may also wonder whether a blood test will be enough, whether a scan is needed or whether your child will have to see another specialist.
There is no standard list of investigations that every child needs. Your paediatrician will usually choose tests based on your child’s symptoms, medical history and examination, with the aim of finding useful answers without putting them through unnecessary testing.
Why Might Your Child Need Tests in the First Place?
Your paediatrician may arrange tests when they need more information to understand your child’s symptoms or confirm a possible cause. The choice of test depends on your child’s medical history, symptoms and examination findings.
Tests can also help monitor a condition or check whether treatment is working. If testing is unlikely to change your child’s care, your paediatrician may recommend observation or follow-up instead, and you can always ask why a particular test is needed.
What Blood Tests Can a Paediatrician Request?
Your paediatrician may request blood tests to check areas such as blood counts, iron status, markers of inflammation, thyroid function, liver function, kidney function or blood glucose. The tests will depend on your child’s symptoms and what your paediatrician is trying to find out.
Only a small amount of blood is usually needed, although the amount depends on the tests requested. If your child needs a blood sample from a vein, you can ask about ways to make the experience more comfortable.
Can Urine, Stool and Other Laboratory Samples Be Tested?
Yes. Depending on your child’s symptoms, your paediatrician may request urine, stool or swab tests to look for infections, inflammation or other health problems. These tests can provide useful information without needing a blood sample.
You may need to follow specific instructions when collecting a sample, including how to store it and when to return it. Even a normal result can make some possible causes less likely and help your paediatrician decide whether further tests, monitoring or specialist care are needed.
Can Blood Tests Help Investigate Allergies, Coeliac Disease or Other Specific Conditions?
Yes. Your paediatrician may arrange targeted blood tests when your child’s symptoms and history suggest a particular condition. For example, coeliac serology may be used when coeliac disease is suspected, while specific IgE blood tests may be considered for suspected IgE-mediated food allergy based on an allergy-focused clinical history.
These tests do not confirm every diagnosis on their own and need to be interpreted alongside your child’s symptoms and examination. Coeliac blood testing is only reliable when your child is eating a gluten-containing diet during the diagnostic process. NICE advises eating some gluten in more than one meal each day for at least six weeks before testing. Allergy test results, meanwhile, need to be interpreted alongside the suspected allergen and your child’s previous reactions.
Clinical Tip
Do not start a gluten-free diet before coeliac testing. If your child has already reduced or stopped eating gluten, tell their healthcare professional, as specialist advice may be needed before testing. If a food is suspected of causing an allergic reaction, do not deliberately reintroduce or challenge it at home without advice from your child’s healthcare professional. In some non-IgE-mediated food allergies, a planned elimination and reintroduction may form part of the diagnostic process under professional guidance.
When Might Your Child Need an X-Ray?
Your child may need an X-ray to check their bones, chest or other areas when your paediatrician needs a clearer picture of a possible problem. It is usually a quick procedure, although your child may need to stay still for a few seconds.
X-rays use ionising radiation, and the amount varies according to the examination. Imaging is recommended when the expected clinical benefit outweighs the radiation risk, and an ultrasound, MRI or another investigation may sometimes provide the information needed without ionising radiation.
What Can an Ultrasound Scan Show?
An ultrasound uses sound waves rather than X-rays, making it a useful way to examine your child’s organs and soft tissues without ionising radiation. Your child may need an ultrasound to check areas such as the kidneys, bladder, liver, abdomen or a particular lump.
The scan is usually painless and involves moving a small probe over the skin with gel. Depending on the area being examined, your child may need to follow simple preparation instructions, such as having a full bladder or avoiding food beforehand.
When Might MRI or CT Imaging Be Considered?
Your child may need an MRI when detailed images of the brain, spine, joints or internal organs are needed. MRI does not use ionising radiation, but your child needs to stay still during the scan, so younger children may sometimes need sedation or an anaesthetic.
CT uses X-rays and can provide detailed images quickly when this is clinically needed. Your paediatrician will choose MRI, CT or another scan based on the specific medical question, rather than one test automatically being better than another.
UK Guidance Note
UK radiation regulations require X-ray and CT examinations to be justified before they are performed and the radiation dose to be kept as low as reasonably practicable while still answering the clinical question. Alternative imaging that uses less or no ionising radiation should also be considered when appropriate.
How Do Common Paediatric Investigations Compare?
| Investigation | What it can assess | Ionising radiation? |
| Blood test | Blood cells, inflammation, iron, organ function, hormones and selected conditions | No |
| Urine/stool test | Infection, inflammation and selected gastrointestinal or urinary problems | No |
| X-ray | Bones, chest and selected structural problems | Yes |
| Ultrasound | Abdominal organs, kidneys, bladder and soft tissues | No |
| MRI | Detailed brain, spine, joints and soft-tissue imaging | No |
| CT | Detailed imaging when speed or specific anatomical information is important | Yes |
| ECG / heart monitor | Heart rhythm and electrical activity | No |
| EEG | Brain electrical activity | No |
| Spirometry / FeNO | Selected respiratory problems, including objective assessment for asthma | No |
The most detailed test is not automatically the best one. Your paediatrician chooses the investigation that is most likely to answer the clinical question with the least unnecessary burden or risk.
Will Your Child Need Sedation or an Anaesthetic for a Scan?
Many children can have imaging while awake, particularly when the scan is quick or they can remain still. MRI takes longer and movement can blur the images, so some younger children or children who find the environment difficult may need additional support, sedation or a general anaesthetic.
If this is being considered, the imaging team will explain the preparation, fasting instructions if relevant and what happens before and after the scan. Do not assume your child will need sedation based on age alone, as the decision depends on the scan and your child’s individual needs.
What Heart Tests Can a Paediatrician Arrange?
If your child has symptoms such as fainting or palpitations, or an unusual heart rhythm is suspected or detected, your paediatrician may arrange heart tests. An ECG is a quick, painless test that records the heart’s electrical activity and rhythm.
If symptoms happen only occasionally, your child may need a portable monitor to record their heart rhythm for longer. More specialised tests, such as exercise testing, may be arranged through a paediatric cardiology service when needed.
What Is an Echocardiogram and When Is It Used?
An echocardiogram, or echo, is an ultrasound scan that looks at your child’s heart, including its structure, movement and blood flow. It may be recommended if your paediatrician hears a heart murmur or your child has symptoms that suggest their heart needs closer assessment.
The scan is usually painless and involves moving an ultrasound probe over your child’s chest. If further assessment is needed, your paediatrician may refer your child to paediatric cardiology for additional heart tests.
What Respiratory Tests Can Be Arranged?
If your child has ongoing wheezing, breathlessness or exercise-related breathing problems, your paediatrician may arrange lung function tests. Spirometry is a common test that measures how well your child’s lungs move air in and out.
For children aged 5 to 16 with a history suggesting asthma, NICE recommends FeNO testing first when available. If this does not confirm the diagnosis, bronchodilator reversibility with spirometry is considered, with other objective tests used if uncertainty remains. Younger children may not always be able to perform these tests reliably, so assessment may rely more on symptoms, clinical review and specialist input when needed.
What Neurological Tests Might a Paediatrician Request?
If your child’s history and examination suggest a possible epileptic seizure, an EEG may be used to support the diagnosis and provide information about the seizure type or epilepsy syndrome. An EEG records the brain’s electrical activity using electrodes placed on the scalp and is not painful, but a normal EEG does not by itself exclude epilepsy.
Brain imaging may also be needed depending on the clinical context. NICE recommends neuroimaging when an underlying structural cause is suspected and generally recommends MRI for children diagnosed with epilepsy, although MRI is not routinely required for some specific epilepsy syndromes. More specialised investigations are usually arranged through paediatric neurology or neurophysiology services.
Can Genetic or Metabolic Tests Be Arranged?
Yes, your paediatrician may consider genetic or metabolic tests when your child’s symptoms, development or family history suggest an underlying condition. These tests are usually guided by your child’s developmental history, pattern of symptoms, examination findings and family history rather than being used as broad screening tests for every unexplained symptom.
Your paediatrician may involve a genetics or metabolic specialist to choose the most appropriate tests. You should also be given clear information about why testing is needed and what the results could mean.
What Other Specialist Investigations Might Be Needed?
If your child’s symptoms need more specialised tests, your paediatrician may refer them to the appropriate specialist. This could include gastroenterology, neurology, audiology, ophthalmology or endocrinology.
Your child may then have focused tests for their specific symptoms, such as hearing, vision or sleep assessments. A referral simply helps your child receive the right expertise when needed.
How Will Your Child Be Prepared for Tests?
Your child’s preparation will depend on the type of test they need. Some tests require no special preparation, while others may involve fasting, drinking fluids or using numbing cream for a blood test.
If your child feels anxious, tell the healthcare team so they can provide suitable support. You can also explain the test honestly in simple language, including that some procedures may feel uncomfortable for a short time.
How Will Your Paediatrician Decide Which Test Your Child Needs?
Your paediatrician will choose a test based on your child’s symptoms, age, medical history and examination findings. The aim is to select an investigation that can answer an important clinical question without unnecessary testing.
You may start with a simple test before moving to more specialised investigations if needed. The best test is not always the most detailed scan; it is the one that provides useful information with the least unnecessary burden or risk.
Why Do Test Results Need the Bigger Picture?
A test result rarely tells the whole story on its own. Your paediatrician will interpret it alongside your child’s symptoms, medical history and examination findings. This is particularly important with conditions such as asthma and epilepsy, where individual tests form only one part of the assessment and a normal result may not completely rule out the suspected condition.
Can a Test Be Inconclusive or Need Repeating?
Yes. A result may occasionally be borderline, affected by how the sample was collected or difficult to interpret without further information. Some tests also need to be repeated over time because your child’s symptoms or measurements can change.
A repeat test does not necessarily mean that something serious has been found. Your paediatrician should explain why another sample, scan or investigation is needed and how the new result could help clarify the next step.
What Happens When the Results Come Back?
Some results are available quickly, while others take longer, depending on the test and whether specialist review is needed. Your paediatrician will explain what the results mean and whether they change your child’s care.
A normal result does not mean your child’s symptoms were not real, while an abnormal result may lead to further tests or specialist review. Make sure you understand what happens next and whether any follow-up is needed.
Myth vs Fact
| Myth | Fact |
| More tests always give a better answer. | No. Tests are most useful when they address a specific clinical question. |
| A normal test means nothing is wrong. | Not necessarily. Some conditions are diagnosed from the overall clinical picture, and further review may still be needed. |
| Every scan exposes your child to radiation. | No. Ultrasound and MRI do not use ionising radiation. |
| A normal EEG rules out epilepsy. | No. NICE specifically advises that EEG should not be used to exclude epilepsy. |
| An allergy blood test can screen for every food allergy. | No. Specific IgE tests should be guided by an allergy-focused clinical history. |
Key Takeaways
- Tests are selected according to your child’s symptoms, history, examination and the clinical question that needs answering.
- Blood, urine and stool tests can investigate a wide range of problems without automatically providing a diagnosis on their own.
- Ultrasound and MRI do not use ionising radiation, while X-ray and CT do.
- X-ray and CT examinations should be justified and use an appropriately optimised radiation dose.
- Allergy and coeliac blood tests need correct clinical interpretation and preparation.
- A normal EEG does not exclude epilepsy.
- Some specialist tests may require referral to cardiology, neurology, genetics or another paediatric service.
- Results can sometimes be normal, borderline or inconclusive, and follow-up may still be appropriate.
Frequently Asked Questions
1. What tests can a paediatrician arrange for your child?
Your paediatrician may arrange blood tests, urine or stool tests, X-rays, ultrasound scans and other investigations depending on your child’s symptoms. The tests are chosen based on their medical history, examination and the specific question your paediatrician needs to answer.
2. Can a paediatrician request blood tests for your child?
Yes. Blood tests can be used to check areas such as blood counts, iron status, markers of inflammation, thyroid function, liver function, kidney function and blood glucose. Your paediatrician will select the tests according to your child’s symptoms and medical history.
3. When might your child need an X-ray?
Your child may need an X-ray when your paediatrician needs to examine their bones, chest or another area more closely. X-rays use ionising radiation, so your paediatrician will only recommend one when the expected benefit outweighs the potential risk.
4. Is an ultrasound scan safe for children?
Ultrasound is generally considered a safe imaging method because it uses sound waves rather than ionising radiation. It can be used to examine areas such as your child’s abdomen, kidneys, bladder, liver and soft tissues.
5. When might your child need an MRI or CT scan?
An MRI may be recommended when detailed images of your child’s brain, spine, joints or internal organs are needed, while CT can provide detailed images quickly when clinically appropriate. Your paediatrician will choose the scan according to your child’s symptoms and the medical question that needs to be answered.
6. What heart tests can a paediatrician arrange?
If your child has symptoms such as fainting or palpitations, or an unusual heart rhythm is suspected or detected, your paediatrician may arrange an ECG or another heart investigation. An echocardiogram, portable heart monitor or more specialised testing may also be considered, sometimes through paediatric cardiology.
7. What tests can be used to investigate breathing problems in children?
If your child has ongoing wheezing, breathlessness or breathing difficulties during exercise, your paediatrician may arrange lung function testing. Spirometry is commonly used, while tests such as FeNO or a bronchodilator response may be considered depending on your child’s symptoms.
8. What neurological tests might your child need?
If your child has possible seizures or other neurological symptoms, your paediatrician may consider an EEG and, depending on the clinical findings, brain imaging or specialist referral. A normal EEG does not exclude epilepsy. An EEG records electrical activity in the brain, while MRI can provide detailed images of the brain and other structures.
9. Can a paediatrician arrange genetic or specialist investigations?
Yes. Genetic or metabolic testing may be considered when your child’s symptoms, development or family history suggest a possible underlying condition. Your paediatrician may involve a specialist in genetics, neurology, gastroenterology, endocrinology or another area when more specialised investigation is needed.
10. What happens after your child’s test results come back?
Some results are available quickly, while others may take longer if specialist analysis is required. Your paediatrician will explain what the results mean, whether further investigations or specialist referral are needed and what happens next with your child’s care.
Final Thoughts: Understanding Your Child’s Tests and Investigations
The tests your child needs will depend on their symptoms, medical history and examination findings. Your paediatrician can explain why a particular investigation is recommended, what it involves and what the results may mean for your child’s care.
If you need a trusted paediatrician in London, you can get in touch with our team at London Paediatric Clinic to discuss your child’s symptoms and arrange an appropriate assessment.
References:
- NHS (2023) Blood tests. Page last reviewed 2 November 2023. Available at: https://www.nhs.uk/tests-and-treatments/blood-tests/
- Department of Health and Social Care (2024) Guidance to the Ionising Radiation (Medical Exposure) Regulations 2017. Updated 4 September 2024. Available at: https://www.gov.uk/government/publications/ionising-radiation-medical-exposure-regulations-2017-guidance/guidance-to-the-ionising-radiation-medical-exposure-regulations-2017
- UK Health Security Agency (2025) National Diagnostic Reference Levels (NDRLs) from 11 December 2025. Updated 11 December 2025. Available at: https://www.gov.uk/government/publications/diagnostic-radiology-national-diagnostic-reference-levels-ndrls/ndrl
- Oxford University Hospitals NHS Foundation Trust (no date) MRI (Magnetic Resonance Imaging). Available at: https://www.ouh.nhs.uk/services/departments/radiology/noc-radiology/noc-radiology-tests/noc-radiology-mri/
- National Institute for Health and Care Excellence (NICE) (2015) Coeliac disease: recognition, assessment and management. NICE guideline NG20. Available at: https://www.nice.org.uk/guidance/ng20
- Great Ormond Street Hospital for Children NHS Foundation Trust (no date) Cardiac screening tests. Available at: https://www.gosh.nhs.uk/wards-and-departments/departments/clinical-specialties/inherited-cardiovascular-diseases/cardiac-screening-tests/
- National Institute for Health and Care Excellence (NICE) (2024) Asthma: diagnosis, monitoring and chronic asthma management (BTS, NICE, SIGN). NICE guideline NG245. Published 27 November 2024. Available at: https://www.nice.org.uk/guidance/ng245
- National Institute for Health and Care Excellence (NICE) (2025) Epilepsies in children, young people and adults. NICE guideline NG217. Published 27 April 2022; updated 30 January 2025. Available at: https://www.nice.org.uk/guidance/ng217
- NHS England Genomics Education Programme (2026) Presentation: Child with developmental delay or intellectual disability. Page last reviewed 4 February 2026. Available at: https://www.genomicseducation.hee.nhs.uk/genotes/in-the-clinic/presentation-child-with-developmental-delay-or-intellectual-disability/
- Cambridge University Hospitals NHS Foundation Trust (2025) How to collect a clean catch urine sample from children. Available at: https://www.cuh.nhs.uk/patient-information/how-to-collect-a-clean-catch-urine-sample-from-children/
- National Institute for Health and Care Excellence (NICE) (2011) Food allergy in under 19s: assessment and diagnosis. Clinical guideline CG116. Available at: https://www.nice.org.uk/guidance/cg116