Bluetooth GATT Characteristic Reference

PLX Spot-Check Measurement (0x2A5E)

org.bluetooth.characteristic.plx_spot_check_measurement

The PLX Spot-check Measurement characteristic, if supported, is used to send Spot-check measurements of SpO2 (Percent oxygen saturation of hemoglobin) and PR (pulse rate). This characteristic is a variable length structure containing the Flags field, the SpO2PR-Spot-Check field, and depending on the contents of the Flags field, the Timestamp field, the Measurement Status field, the Device and Sensor Status field, and/or the Pulse Amplitude Index 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	PLX Spot-Check Measurement
UUID	0x2A5E
Type	org.bluetooth.characteristic.plx_spot_check_measurement
XML Root	Characteristic
Source File	org.bluetooth.characteristic.plx_spot_check_measurement.xml
Field Count	7

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
SpO2PR-Spot-Check - SpO2	Mandatory	SFLOAT	org.bluetooth.unit.percentage	0	Unit is percentage with a resolution of 1
SpO2PR-Spot-Check - PR	Mandatory	SFLOAT	org.bluetooth.unit.period.beats_per_minute	0	Unit is beats per minute with a resolution of 1
Timestamp	C1	N/A	-	-	Unit is smallest unit in seconds with a resolution of 1
Measurement Status	C2	16bit	-	-	-
Device and Sensor Status	C3	24bit	-	-	-
Pulse Amplitude Index	C4	SFLOAT	org.bluetooth.unit.percentage	0	Unit is percentage with a resolution of 1

Bit Map

Bit-level enumerations extracted from the XML BitField definition.

Field	Bit	Size	Name	0 Means	1 Means
Flags	0	1	Timestamp field is present	False	True
Flags	1	1	Measurement Status Field Present	False	True
Flags	2	1	Device and Sensor Status Field Present	False	True
Flags	3	1	Pulse Amplitude Index field is present	False	True
Flags	4	1	Device Clock is Not Set	False	True
Measurement Status	5	1	Measurement Ongoing	False	True
Measurement Status	6	1	Early Estimated Data	False	True
Measurement Status	7	1	Validated Data	False	True
Measurement Status	8	1	Fully Qualified Data	False	True
Measurement Status	9	1	Data from Measurement Storage	False	True
Measurement Status	10	1	Data for Demonstration	False	True
Measurement Status	11	1	Data for Testing	False	True
Measurement Status	12	1	Calibration Ongoing	False	True
Measurement Status	13	1	Measurement Unavailable	False	True
Measurement Status	14	1	Questionable Measurement Detected	False	True
Measurement Status	15	1	Invalid Measurement Detected	False	True
Device and Sensor Status	0	1	Extended Display Update Ongoing	False	True
Device and Sensor Status	1	1	Equipment Malfunction Detected	False	True
Device and Sensor Status	2	1	Signal Processing Irregularity Detected	False	True
Device and Sensor Status	3	1	Inadequite Signal Detected	False	True
Device and Sensor Status	4	1	Poor Signal Detected	False	True
Device and Sensor Status	5	1	Low Perfusion Detected	False	True
Device and Sensor Status	6	1	Erratic Signal Detected	False	True
Device and Sensor Status	7	1	Nonpulsatile Signal Detected	False	True
Device and Sensor Status	8	1	Questionable Pulse Detected	False	True
Device and Sensor Status	9	1	Signal Analysis Ongoing	False	True
Device and Sensor Status	10	1	Sensor Interface Detected	False	True
Device and Sensor Status	11	1	Sensor Unconnected to User	False	True
Device and Sensor Status	12	1	Unknown Sensor Connected	False	True
Device and Sensor Status	13	1	Sensor Displaced	False	True
Device and Sensor Status	14	1	Sensor Malfunctioning	False	True
Device and Sensor Status	15	1	Sensor Disconnected	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.
  // Parse spo2pr_spot_check_spo2 (SFLOAT) according to Bluetooth format rules.
  // Parse spo2pr_spot_check_pr (SFLOAT) according to Bluetooth format rules.
  // Parse timestamp (N/A) according to Bluetooth format rules.
  // Parse measurement_status (16bit) according to Bluetooth format rules.
  // Parse device_and_sensor_status (24bit) according to Bluetooth format rules.
  // Parse pulse_amplitude_index (SFLOAT) according to Bluetooth format rules.
  return { flags, spo2pr_spot_check_spo2, spo2pr_spot_check_pr, timestamp, measurement_status, device_and_sensor_status };
}

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 PLX Spot-Check Measurement in Bluetooth GATT?

PLX Spot-Check Measurement is defined as a Bluetooth GATT characteristic entry with type org.bluetooth.characteristic.plx_spot_check_measurement and UUID 0x2A5E.

What UUID identifies PLX Spot-Check Measurement?

The UUID for PLX Spot-Check Measurement is 0x2A5E.

How should I parse PLX Spot-Check Measurement?