Screening aid only. Anyone who looks unwell, is deteriorating, or who you are worried about is urgent whatever the numbers say. A normal set of observations in someone who looks wrong is a reason to escalate, not to relax.
Babies and children under 5
Read this before the numbers. In a child under 5, and especially under 1,
how they look and behave outperforms every measurement you can take. In a study of
thousands of children assessed in general practice, impaired response to social cues was the feature
that triggered the majority of both intermediate and high-risk classifications; abnormal vital signs
contributed to a small fraction. Numbers confirm what behaviour has already told you.
| Age | Pulse, bpm | Breathing, per min | Systolic BP, rough guide |
|---|---|---|---|
| Under 1 year | 110–160 | 30–40 | 70–90 |
| 1–2 years | 100–150 | 25–35 | 80–95 |
| 2–4 years | 95–140 | 25–30 | 80–100 |
| Oxygen saturation, all ages | 96–100% on air. 95% or below is a concern in a child under 5, which is a higher threshold than in an adult | ||
| Temperature | 36.1–37.9 °C. Below 36 °C is as concerning as a fever, and babies with serious infection are often cold rather than hot | ||
A rule of thumb for the lowest acceptable systolic pressure in a child: 70 plus twice the age in years. Below that is shock. But blood pressure in a child is the last thing to fall, and it is not the observation that will warn you.
Breathing rate thresholds that matter, by age
These are the figures used in UK assessment of a feverish child, and they are age-specific because a rate that is normal at three months is alarming at three years.
| Age | Breathing faster than this is a red flag |
|---|---|
| 0–5 months | 60 per minute |
| 6–12 months | 50 per minute |
| Over 12 months | 40 per minute |
How sick is this child? The three-band assessment used in the UK
NICE stratifies unwell children under 5 into three bands, and the rule is that the highest single feature present sets the band — one red feature makes a child high risk however well everything else looks.
| Reassuring | Intermediate — needs seeing | High risk — urgent | |
|---|---|---|---|
| Colour | Normal skin, lips and tongue | Pallor reported by a parent or carer | Pale, mottled, ashen or blue |
| Behaviour the most important row | Responds normally, content or smiling, stays awake or wakes quickly, strong normal cry or not crying | Not responding normally to you, no smile, wakes only with prolonged effort, less active than usual | No response to social cues at all, does not wake or does not stay awake, weak high-pitched or continuous cry — or simply that an experienced person thinks the child appears ill |
| Breathing | Normal | Nasal flaring; rate above the age threshold above; oxygen saturation 95% or below; crackles | Grunting; rate above 60; moderate or severe indrawing of the chest |
| Hydration and feeding | Moist mouth, normal skin, feeding normally | Dry mouth, poor feeding in a baby, capillary refill 3 seconds or more, passing less urine or fewer wet nappies | Reduced skin turgor — skin that stays pinched |
| Other | None of the below | Fever 5 days or more; rigors; a swollen limb or joint; not using or not weight-bearing on a limb; 3–6 months with a temperature of 39 °C or above | Under 3 months with a temperature of 38 °C or above; a non-blanching rash; a bulging fontanelle; neck stiffness; a prolonged or focal seizure; focal neurological signs |
What to do, and the five things worth knowing that are not obvious
- Any high-risk feature: 999 or an immediate assessment. Intermediate: seen face to face the same day. Reassuring: care at home with a clear plan for what would change that.
- A baby under 1 month with a temperature of 38 °C or above is a medical emergency, whatever else is normal, and needs hospital assessment and antibiotics within the hour. Under 3 months it is a red feature. This is the single hardest threshold for parents to believe, because the baby often looks well.
- Do not use how high the fever is, or how long it has lasted, to judge how serious it is. Neither predicts serious illness. A fever lasting 5 days or more prompts a different question — assessment for Kawasaki disease — rather than a higher temperature reading.
- The classic meningitis signs are frequently absent in babies. Neck stiffness, a bulging fontanelle and a high-pitched cry are all commonly missing in infants with bacterial meningitis, so their absence excludes nothing. See sepsis and meningitis.
- An unexplained fast pulse puts a child in at least the intermediate band on its own, and is the observation most often noted and not acted on.
- Wet nappies are a vital sign. Count them, and say the number. Eight to twelve hours without one in a baby is significant, and it is a measurement any parent can make.
Your assessment counts, and it is treated as evidence. UK guidance says explicitly that a parent's report of fever should be taken seriously even without a thermometer reading, and that concern this illness is different from previous ones is meaningful. If you are told otherwise, that is not what the guidance says.
Children and young people, 5 to 17
Screening aid only. Any child who looks unwell, is deteriorating, or who you are worried about is urgent whatever the numbers say. A normal set of observations in a child who looks wrong is a reason to escalate, not to relax — children compensate well and then fail suddenly, and the numbers move last.
| Vital sign | Age | Normal | Alert — reassess | Emergency — call 999 |
|---|---|---|---|---|
| Pulse (bpm) | 5–6 y | 80–120 | 70–79 or 121–140 | <70 or >140, or irregular / absent |
| 7–9 y | 75–118 | 65–74 or 119–140 | <65 or >140, or irregular / absent | |
| 10–11 y | 75–118 | 60–74 or 119–140 | <60 or >140, or irregular / absent | |
| 12–15 y | 60–100 | 50–59 or 101–120 | <50 or >120, or irregular / absent | |
| 16–17 y | 60–100 | 50–59 or 101–120 | <50 or >130, or irregular / absent | |
| Breathing (/min) | 5–6 y | 20–28 | 16–19 or 29–35 | <16 or >35, gasping, or not breathing |
| 7–9 y | 18–25 | 15–17 or 26–32 | <15 or >32, gasping, or not breathing | |
| 10–11 y | 18–25 | 14–17 or 26–30 | <14 or >30, gasping, or not breathing | |
| 12–17 y | 12–20 | 9–11 or 21–25 | <9 or >25, gasping, or not breathing | |
| Oxygen saturation | All ages | 95–100% | 90–94% | <90%, or blue lips / fingertips at any reading |
| Blood pressure | 5–6 y | ~95–110 / 56–72 | Systolic 80–94 or >115 | Systolic <80 with symptoms, or shock |
| 7–9 y | ~100–115 / 58–76 | Systolic 85–99 or >120 | Systolic <85 with symptoms, or shock | |
| 10–15 y | ~105–130 / 61–83 | Systolic 90–104 or >140 | Systolic <90 with symptoms, or shock | |
| 16–17 y | <120 / 80 | 120–139/80–89, or systolic 90–99 | Systolic <90 with symptoms, or ≥180/120 | |
| Temperature | All ages | 36.1–37.9 °C | 38.0–39.4 °C | ≥40.0 °C or <35.0 °C |
| Blood glucose known diabetics | All ages | 4.0–7.0 mmol/L | 3.0–3.9 — fast-acting sugar, recheck at 15 min | <3.0 with drowsiness or seizure, or >15 with vomiting / drowsiness |
| Consciousness (AVPU) | All ages | A — alert and orientated | V — responds to voice only | P — pain only, or U — unresponsive |
Call 999 immediately, whatever the numbers say
- Chest pain, blue lips or face, unresponsiveness, a seizure lasting over five minutes, signs of anaphylaxis, suspected stroke (FAST), severe bleeding, suspected spinal injury.
- Any child you are seriously worried about. This is not a softener — the instinct of an experienced adult who thinks a child looks wrong outperforms most single measurements, and the charts exist to support that judgement rather than to overrule it.
- In a younger child, watch the work of breathing before the rate. Nasal flaring, tracheal tug, grunting and chest recession appear before the numbers move, and oxygen saturation falls late. A child working hard to breathe with a normal saturation is a sicker child than the reading suggests.
Adults
The two blood pressure numbers, in plain terms. The top number
is the pressure while the heart is squeezing; the bottom number is the pressure while
it is relaxing between beats. In an emergency it is almost always the top number that
matters, because that is what falls when someone is bleeding, septic or in shock. For deciding
whether someone's usual blood pressure is healthy or too high, both numbers count and the categories are
set out on the blood pressure chapter — a different question
from the one this page is answering.
An adult chart works differently, and it is worth knowing why. Children
have narrow, age-banded normal ranges and deteriorate along a predictable path. Adults have one set
of ranges but enormous individual variation — a trained athlete resting at 45 bpm and someone
with COPD whose usual saturation is 89% are both entirely well. What matters in an adult is
the deviation from their own baseline and the direction of travel, which is why hospitals
score the whole set together rather than reading rows one at a time.
| Vital sign | Normal | Alert — reassess and escalate | Emergency — call 999 |
|---|---|---|---|
| Pulse | 60–100 bpm | 50–59 or 101–130 | <40 or >130, or irregular and newly so, or absent |
| Breathing | 12–20 /min | 9–11 or 21–24 | <8 or ≥25, gasping, or not breathing |
| Oxygen saturation | 96–100% | 94–95% | <92%, or <88% in someone with known COPD on their usual target, or any new cyanosis |
| Blood pressure the top number is the one to read here | Top number 110–139 | Top number 100–109 — lower than usual for them. Or 180 and above | Top number 90 or below, or a drop of 40 from their own usual, or 180 and above with symptoms such as chest pain, breathlessness or confusion |
| Temperature | 36.1–37.9 °C | 35.1–36.0 or 38.0–39.0 | ≥39.1 with other red flags, or ≤35.0 |
| Blood glucose diabetics | 4.0–7.0 mmol/L | 3.5–3.9 — fast-acting sugar, recheck at 15 min | <3.0, or drowsy at any low reading, or high with vomiting and deep breathing |
| Consciousness (AVPU) | A — alert and orientated | New confusion, even with normal numbers | V, P or U — responds to voice or pain only, or unresponsive |
The four adult-specific traps
- A respiratory rate of 25 or more is one of the strongest single predictors of deterioration in an adult, and it is the observation most often estimated rather than counted. Count it for a full minute, without telling them you are doing it.
- New confusion in an older adult is a red flag, not a personality. It is frequently the first sign of infection, sepsis, hypoglycaemia or a stroke, and it is routinely attributed to dementia or age.
- Beta blockers blunt the pulse response. Someone bleeding or septic on a beta blocker may not mount the tachycardia you are expecting. The absence of a fast pulse is not the absence of shock.
- Two or three mildly abnormal readings together are more concerning than one very abnormal one. That is the whole basis of the scoring systems hospitals use, and it is the part a single-row chart cannot express.
Older adults, and why they present differently
- Fever is often absent in serious infection, and a temperature below 36 °C carries the same weight as a high one.
- Falls, confusion and "off legs" are presentations of illness, not diagnoses. A previously mobile person who cannot stand today has something acute going on.
- Pain is frequently absent or atypical — heart attacks present as breathlessness, nausea or collapse rather than chest pain more often with age and in diabetes.
Call 999 regardless of the numbers for: chest pain, blue lips or face,
unresponsiveness, a seizure over five minutes, signs of anaphylaxis, suspected stroke, severe
bleeding, suspected spinal injury — or anyone, of any age, you are seriously worried about.