Conversions, A1C & GMI

a1cDelta

Import: @glucoseiq/core

a1cDelta(current: number, previous: number): number

Calculates the change (delta) between two A1C values.

Returns: Delta (current - previous)

Throws: If either value is invalid

a1cToGMI

Import: @glucoseiq/core

a1cToGMI(a1c: number): number

Maps a laboratory A1C value through estimated average glucose before applying the GMI equation.

This legacy compatibility result is not a CGM-derived GMI. GMI is defined from mean CGM glucose, not from laboratory A1C. Use estimateGMI with measured mean CGM glucose for new work.

Returns: Legacy compatibility result derived through eAG

Throws: If A1C is not a positive finite number

Deprecated: Use estimateGMI with mean CGM glucose.

a1cTrend

Import: @glucoseiq/core

a1cTrend(readings: number[]): 'increasing' | 'decreasing' | 'stable' | 'insufficient data'

Determines the trend of A1C values over time.

Returns: 'increasing' | 'decreasing' | 'stable' | 'insufficient data'

convertGlucoseUnit

Import: @glucoseiq/core

convertGlucoseUnit(input: { unit: GlucoseUnit; value: number }): ConversionResult

Converts a glucose value between mg/dL and mmol/L.

Returns: Object with converted value and new unit

Throws: If value is not a finite number or is negative/zero

Throws: If unit is not a supported glucose unit

See: https://wwwn.cdc.gov/Nchs/Data/Nhanes/Public/2021/DataFiles/BIOPRO_L.htm

estimateA1CFromAverage

Import: @glucoseiq/core

estimateA1CFromAverage(avgGlucose: number, unit: GlucoseUnit = MG_DL): number

Estimates A1C from average glucose.

Returns: Estimated A1C

See: https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html

estimateA1CFromAvgGlucose

Import: @glucoseiq/core

estimateA1CFromAvgGlucose(avgMgDl: number): number

Estimates A1C (percentage) from average glucose in mg/dL.

Returns: Estimated A1C value (percentage)

See: https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html

estimateAvgGlucoseFromA1C

Import: @glucoseiq/core

estimateAvgGlucoseFromA1C(a1c: number): number

Estimates average glucose (mg/dL) from an A1C value (percentage).

Returns: Estimated average glucose in mg/dL

See: https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html

estimateEAG

Import: @glucoseiq/core

estimateEAG(a1c: number): number

Estimates eAG (estimated average glucose, mg/dL) from an A1C value and rejects non-positive or non-finite input.

Returns: Estimated average glucose (mg/dL)

Throws: If a1c is not a positive finite number

See: https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html

estimateGMI

Import: @glucoseiq/core

estimateGMI(valueOrOptions: string | number | EstimateGMIOptions, unit?: GlucoseUnit): number

Estimates Glucose Management Indicator (GMI) from mean CGM glucose.

Returns: GMI percentage rounded to one decimal place

Throws: If unit is required but not provided when input is a number.

Throws: If the glucose unit is unsupported.

Throws: If the glucose value is not a positive number.

Throws: If a string input cannot be parsed.

See: https://doi.org/10.2337/dc18-1581

formatA1C

Import: @glucoseiq/core

formatA1C(val: number): string

Formats an A1C value as a percent string (e.g., "7.2%").

Returns: A1C as string with percent sign

getA1CCategory

Import: @glucoseiq/core

getA1CCategory(a1c: number, thresholds?: { normalMax?: number; prediabetesMax?: number }): 'normal' | 'prediabetes' | 'diabetes' | 'invalid'

Returns the CDC category for an A1C value (normal, prediabetes, diabetes, or invalid). Uses CDC defaults: normal below 5.7%, prediabetes from 5.7% to below 6.5%, and diabetes at 6.5% or above. Explicit custom maxima are inclusive. At runtime, nullish threshold objects or fields use the CDC defaults.

Returns: 'normal' | 'prediabetes' | 'diabetes' | 'invalid'

See: https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html

isA1CInTarget

Import: @glucoseiq/core

isA1CInTarget(a1c: number, target: [number, number] = [6.5, 7.0], thresholds?: { max?: number; min?: number }): boolean

Checks if an A1C value is within a target range.

Returns: True if in target range

isValidA1C

Import: @glucoseiq/core

isValidA1C(value: unknown): boolean

Returns whether a value is finite and greater than 0 but less than 20.

Returns: True if value is a valid A1C percentage

mgDlToMmolL

Import: @glucoseiq/core

mgDlToMmolL(val: number): number

Converts a glucose value from mg/dL to mmol/L.

Returns: Value in mmol/L

Throws: If val is not a finite number or is negative/zero

See: https://wwwn.cdc.gov/Nchs/Data/Nhanes/Public/2021/DataFiles/BIOPRO_L.htm

import { mgDlToMmolL } from '@glucoseiq/core'

const mgdl: number = 180
const result = mgDlToMmolL(mgdl)
console.log(result) // 10.0

mmolLToMgDl

Import: @glucoseiq/core

mmolLToMgDl(val: number): number

Converts a glucose value from mmol/L to mg/dL.

Returns: Value in mg/dL

Throws: If val is not a finite number or is negative/zero

See: https://wwwn.cdc.gov/Nchs/Data/Nhanes/Public/2021/DataFiles/BIOPRO_L.htm

import { mmolLToMgDl } from '@glucoseiq/core'

const mmol: number = 5.5
const result = mmolLToMgDl(mmol)
console.log(result) // 99