timeinrange

Timeinrange, often written as Time in Range (TIR), is a glycemic metric that expresses the percentage of time a person’s glucose values stay within a defined target range. It is typically based on continuous glucose monitoring (CGM) data and is calculated over a set period, such as 24 hours or several days. Related metrics include Time Below Range (TBR) and Time Above Range (TAR), which quantify time spent below or above the target range.

Measurement and interpretation: CGM devices provide glucose readings at frequent intervals, commonly every 5 minutes. TIR is computed as the proportion of readings that fall within the chosen target range, with possible interpolation for brief data gaps. TIR serves as a practical indicator of how well a person’s glucose levels are controlled and is associated with the risk of hypo- or hyperglycemic events.

Target ranges and guidelines: For many adults with diabetes, guidelines commonly recommend aiming for a TIR of about 70% or higher, with TBR kept below around 4% and TAR below about 25% within a target range of 70–180 mg/dL. Targets can vary by age, pregnancy status, comorbidities, and individual treatment goals, so clinicians tailor targets to each patient.

Clinical use and research: TIR is used to guide therapy decisions, adjust insulin dosing or other treatments, and monitor CGM performance. It is also a widely used endpoint in diabetes research to evaluate interventions and the effectiveness of new technologies or treatment strategies.

Limitations: TIR depends on the chosen target range and on data quality. Sensor inaccuracy, data gaps, and differences between CGM devices can affect value interpretation and cross-study comparability. TIR complements other measures such as glycated hemoglobin (A1C).