Age Related Reference Ranges

TL;DR

• Laboratory “normal” values differ by age and are used to interpret test results in the context of a person’s age.
• Common examples include hemoglobin, cholesterol, and blood pressure, each having distinct ranges for infants, adults, and elderly people.
• These ranges guide clinical decisions but can vary by laboratory and measurement method.

Definition

Age-related reference ranges are the normal values of various laboratory tests and measurements that are specific to different age groups, providing a basis for interpreting test results and determining whether they fall within the normal range for a person’s age.

Explanation

Reference ranges for laboratory tests and vital signs change with age because physiological demands and body systems vary across the lifespan. Applying an age-appropriate range helps determine whether a result is expected for that age group or indicates a potential health concern. Ranges are not absolute: they may differ between laboratories and depend on measurement methods, so clinical interpretation should consider the specific laboratory’s reference intervals and the patient’s context.

Examples

Hemoglobin

• Adults: 12–16 g/dL
• Infants: 13–26 g/dL
• Elderly: 11–15 g/dL

Interpretation example from source:

• An elderly individual with hemoglobin of 12 g/dL may be considered normal for their age; the same hemoglobin level in a younger adult may be considered low and indicate anemia.

Cholesterol

• Adults (recommended): below 200 mg/dL
• Children and teenagers: 100–170 mg/dL
• Older adults: 200–239 mg/dL

Interpretation example from source:

• A child with cholesterol of 200 mg/dL may be considered high and require further evaluation, whereas the same value in an older adult may be within the normal range for their age.

Blood pressure

• Adults: 90/60 mmHg to 120/80 mmHg
• Infants and children: 70/40 mmHg to 100/60 mmHg
• Elderly: 110/70 mmHg to 130/80 mmHg

Use cases

• Provide age-appropriate context for interpreting laboratory and vital-sign results.
• Help healthcare providers guide decision making and treatment plans based on age-specific norms.

Notes or pitfalls

• Reference ranges may vary depending on the specific laboratory and the methods used to measure the test results.
• Applying a non–age-specific reference range can lead to misclassification (for example, labeling a value as abnormal when it is normal for the patient’s age).
• Discuss any concerns or questions about test results with a healthcare provider who can interpret results in context.

Related terms

• Reference range
• Laboratory test
• Anemia
• Blood pressure