Psychology
Autism: early signs, diagnosis and support
Early signs of autism by age, the difference between a late talker and an autistic child, how diagnosis works, what support helps — and the 'cures' that harm.
27 Sept 202610 min read
Screening
Also known as Screening test
Screening is testing people who feel well, to find a condition earlier than symptoms would. It is only worth doing when finding the condition early genuinely changes what happens next.
A screening test is not a diagnostic test. It is applied to people without symptoms and is designed to sort them into those who probably do not have the condition and those who need a proper diagnostic test next. An abnormal screening result is therefore a reason for further testing, not a diagnosis — and this is the single most misunderstood thing about it.
Why not screen for everything
Screening a large well population inevitably produces false positives, and each one leads to further tests, cost and anxiety in somebody who was never ill. It can also find disease that would never have caused harm in that person's lifetime — overdiagnosis — and treating it does damage without benefit. A programme is justified only when the condition is common enough, detectable early, and better treated early than late.
| Test | Looking for | Typically offered to |
|---|---|---|
| All adults, periodically | ||
| or | Adults with risk factors | |
| Raised | Adults with cardiovascular risk | |
| Cervical screening | Pre-cancerous change | Women within the eligible age range |
Screening is also the reason a normal result is worth having in writing: it establishes a baseline, and a later change from a person's own normal is often more informative than any single value read against a population range.
Where this comes up
Tests & Diagnostics
HbA1c: What the Number on Your Diabetes Report Means
HbA1c is your average blood sugar over the last two to three months. What the bands mean, what a good target is, and the common conditions that make it unreliable.
31 Aug 202610 min read
General Medicine
The Annual Health Check: What Is Worth Testing
A useful yearly check is six or seven cheap tests, not a fifty-test package. What to ask for at each age, what to skip, and how to read the report.
30 Aug 202610 min read
Pediatrics
Fever in Children: What to Do Tonight and When to Go to Hospital
A fever is the body fighting an infection. Most settle at home. These are the signs that mean go now, how to dose paracetamol safely, and what not to do.
28 Aug 202611 min read
Related terms
- Differential diagnosisDifferentials, The list of possibilitiesA differential diagnosis is the list of conditions that could explain a person's symptoms, ranked by likelihood and by danger. It is how a doctor thinks before a diagnosis is reached, and the reason questions and tests follow the order they do.
- MalignantCancerousMalignant describes a growth that can invade the tissue around it and spread to other parts of the body. It is the opposite of benign, which stays where it started.
- PrognosisOutlookA prognosis is the expected course of a condition — how it is likely to develop and what the chances of recovery are. It is a statement about probability across many people, not a prediction about one.
- HbA1cGlycated haemoglobin, A1cHbA1c measures the proportion of haemoglobin that has sugar stuck to it, which reflects the average blood glucose over roughly the past three months. It needs no fasting and is used both to diagnose diabetes and to judge how well it is controlled.
- Blood pressureBP, Arterial pressureBlood pressure is the force of blood against the artery walls, written as two numbers in millimetres of mercury: the higher one is the pressure as the heart squeezes, the lower one the pressure as it refills. It varies through the day, so a diagnosis is never made on one reading.
- ProphylaxisPreventive treatment, ProphylacticProphylaxis is treatment given to prevent a disease rather than to cure one. Vaccines, malaria tablets taken before travel and antibiotics given before surgery are all examples.
- PlaceboDummy treatment, Placebo effectA placebo is a treatment with no active ingredient, used in trials as the comparison against which a real medicine is judged. The placebo effect is the genuine improvement people report after receiving one.