Body Composition Measurement (0x2A9C)

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.

Field Specification

Parsed field definitions from the source XML value structure.

Bit Map

Bit-level enumerations extracted from the XML BitField definition.

Byte Layout and Decode

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

function decodePayload(dataView, offset = 0) {
  // Parse flags (16bit) according to Bluetooth format rules.
  const body_fat_percentage = dataView.getUint16(offset + 0, true);
  // Parse time_stamp (N/A) according to Bluetooth format rules.
  const user_id = dataView.getUint8(offset + 2);
  const basal_metabolism = dataView.getUint16(offset + 3, true);
  const muscle_percentage = dataView.getUint16(offset + 5, true);
  const muscle_mass_kilograms = dataView.getUint16(offset + 7, true);
  const muscle_mass_pounds = dataView.getUint16(offset + 9, true);
  const fat_free_mass_kilograms = dataView.getUint16(offset + 11, true);
  const fat_free_mass_pounds = dataView.getUint16(offset + 13, true);
  return { flags, body_fat_percentage, time_stamp, user_id, basal_metabolism, muscle_percentage };
}

Use Cases and Integration Notes

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

Related Links

Last updated: 2026-03-04