Bluetooth GATT Characteristic Reference

Glucose Measurement Context (0x2A34)

org.bluetooth.characteristic.glucose_measurement_context

The Glucose Measurement Context characteristic is a variable length structure containing a Flags field, a Sequence Number field and, based upon the contents of the Flags field, may contain a Carbohydrate ID field, Carbohydrate field, Meal field, Tester-Health field, Exercise Duration field, Exercise Intensity field, Medication ID field, Medication field and a HbA1c field.

Quick Summary

Payload length is profile-defined or variable based on field formats. This page is generated from official GATT XML and presented as implementation-ready guidance.

At a Glance

Key reference details for BLE implementation, interoperability testing, and AI-assisted troubleshooting.

Property	Value
Name	Glucose Measurement Context
UUID	0x2A34
Type	org.bluetooth.characteristic.glucose_measurement_context
XML Root	Characteristic
Source File	org.bluetooth.characteristic.glucose_measurement_context.xml
Field Count	14

Field Specification

Parsed field definitions from the source XML value structure.

Field	Requirement	Format	Unit	Exponent	Notes
Flags	Mandatory	8bit	-	-	These flags define which data fields are present in the Characteristic value
Sequence Number	Mandatory	uint16	-	-	-
Extended Flags	C1	8bit	-	-	C1: Field exists if the key of bit 7 of the Flags field is set to 1
Carbohydrate ID	C2	uint8	-	-	C2: Field exists if the key of bit 0 of the Flags field is set to 1
Carbohydrate - units of kilograms	C2	SFLOAT	org.bluetooth.unit.mass.kilogram	-3	C2: Field exists if the key of bit 0 of the Flags field is set to 1
Meal	C3	uint8	-	-	C3: Field exists if the key of bit 1 of the Flags field is set to 1
Tester	C4	nibble	-	-	C4: Field exists if the key of bit 2 of the Flags field is set to 1
Health	C4	nibble	-	-	C4: Field exists if the key of bit 2 of the Flags field is set to 1
Exercise Duration	C5	uint16	org.bluetooth.unit.time.second	-	C5: Field exists if the key of bit 3 of the Flags field is set to 1
Exercise Intensity	C5	uint8	org.bluetooth.unit.percentage	-	C5: Field exists if the key of bit 3 of the Flags field is set to 1
Medication ID	C6	uint8	-	-	C6: Field exists if the key of bit 4 of the Flags field is set to 1
Medication - units of kilograms	C6	SFLOAT	org.bluetooth.unit.mass.kilogram	-6	C6: Field exists if the key of bit 4 of the Flags field is set to 1, C8: Field exists if the key of bit 5 of the Flags field is set to 0
Medication - units of liters	C6	SFLOAT	org.bluetooth.unit.volume.litre	-3	C6: Field exists if the key of bit 4 of the Flags field is set to 1, C9: Field exists if the key of bit 5 of the Flags field is set to 1
HbA1c	C7	SFLOAT	org.bluetooth.unit.percentage	-	C7: Field exists if the key of bit 6 of the Flags field is set to 1

Bit Map

Bit-level enumerations extracted from the XML BitField definition.

Field	Bit	Size	Name	0 Means	1 Means
Flags	0	1	Carbohydrate ID And Carbohydrate Present	False	True
Flags	1	1	Meal Present	False	True
Flags	2	1	Tester-Health Present	False	True
Flags	3	1	Exercise Duration And Exercise Intensity Present	False	True
Flags	4	1	Medication ID And Medication Present	False	True
Flags	5	1	Medication Value Units	kilograms	liters
Flags	6	1	HbA1c Present	False	True
Flags	7	1	Extended Flags Present	False	True

Byte Layout and Decode

Payload length is profile-defined or variable based on field formats.

function decodePayload(dataView, offset = 0) {
  // Parse flags (8bit) according to Bluetooth format rules.
  const sequence_number = dataView.getUint16(offset + 0, true);
  // Parse extended_flags (8bit) according to Bluetooth format rules.
  const carbohydrate_id = dataView.getUint8(offset + 2);
  // Parse carbohydrate_units_of_kilograms (SFLOAT) according to Bluetooth format rules.
  const meal = dataView.getUint8(offset + 3);
  // Parse tester (nibble) according to Bluetooth format rules.
  // Parse health (nibble) according to Bluetooth format rules.
  const exercise_duration = dataView.getUint16(offset + 4, true);
  const exercise_intensity = dataView.getUint8(offset + 6);
  return { flags, sequence_number, extended_flags, carbohydrate_id, carbohydrate_units_of_kilograms, meal };
}

Use Cases and Integration Notes

BLE Telemetry

Map characteristic values into dashboards and alerts for device observability.

Firmware Regression

Compare decoded fields across builds to detect protocol or scaling changes.

App Integration

Build stable parsing paths that convert raw payloads into typed app models.

Implementation Checklist

Validate payload length and mandatory fields before decode.
Decode with Bluetooth-specified signedness, unit, and exponent handling.
Convert units at presentation boundaries to avoid drift in business logic.
Persist raw packets and decoded values for reproducible troubleshooting.

FAQ

What is Glucose Measurement Context in Bluetooth GATT?

Glucose Measurement Context is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.glucose_measurement_context and UUID 0x2A34.

What UUID identifies Glucose Measurement Context?

The UUID for Glucose Measurement Context is 0x2A34.

How should I parse Glucose Measurement Context?