XK Essence

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Visualization Guidance

For guidance on visualizing data from this device, see XK300 Essence.

• Data Transfer: Via Tenovi Gateway
• Sensor Code: 39
• On-Device Measurement Storage: Yes – measurements taken outside of range of the Tenovi Gateway will be saved locally and uploaded the next time the Gateway is in range, as long as the device is not unplugged.
• Supports tracking multiple devices per gateway via Sensor IDs: No – only one device with this Sensor Code can be assigned to a gateway at one time.

Note

The XK Essence offloads data to the Gateway every 6hrs. This data is grouped into 1hr intervals with the following metrics.

Note

The Metrics noted as “Non-Vital” in the tables on each device page are not counted towards the # of days with data in our RPM billing reports (i.e. these Metrics are not considered “physiologic parameters” under current Medicare guidelines).

Metrics

Name	API Format	Value 1	Value 2	Is Vital?*
XK Heart Rate Statistics Measurement	xk_heart_rate_statistics	Median Heart Rate (BPM)	Heart Rate POBC Score	✅
XK Respiratory Rate Statistics Measurement	xk_respiratory_rate_statistics	Median Respiratory Rate (Breaths per Minute)	Respiratory Rate POBC Score	✅
XK Sleep Measurement	xk_sleep_data	Sleep Duration (minutes)	In-Bed Duration (minutes)	✅
XK Hardware Status Data Hardware debugging only, not for clinical use	xk_hardware_status_data	Hardware Sensitivity Index	Hardware Vacancy Count	❌
XK Discovery Log Hardware debugging only, not for clinical use	xk_discovery_log	Serial number of the XK unit discovered in discovery mode	The current RSSI of the connection	❌

Additional Data Included in Filter Params

xk_heart_rate_statistics

Key	Possible Values	Description
heart_rate_mean	40 to 130 0 = invalid	Mean heart rate (BPM)
heart_rate_variance	0 to 2025	Variance of heart (BPM^2)
heart_rate_measurement_count	0 to 1530	Number of heart rate measurements (count 3 seconds)
heart_rate_integrity_score	N/A	Average high-reliability heart rate measurements over the sampling time (count)
heart_rate_deviations	0 to 75	Count of high-reliability heart rate data points exceeding 2σ from the mean within the specified interval
measurement_index	0 to 9999	Gateway internal message counter, this provides a way to correlate measurements together

xk_respiratory_rate_statistics

Key	Possible Values	Description
respiratory_rate_mean	40 to 130 0 = invalid	Mean respiratory rate (RPM)
respiratory_rate_variance	0 to 2025	Variance of respiratory (RPM^2)
respiratory_rate_measurement_count	0 to 1530	Number of respiratory rate measurements (count 3 seconds)
respiratory_rate_integrity_score	N/A	Average high-reliability respiratory rate measurements over the sampling time (count)
respiratory_rate_deviations	0 to 75	Count of high-reliability respiratory rate data points exceeding 2σ from the mean within the specified interval
measurement_index	0 to 9999	Gateway internal message counter, this provides a way to correlate measurements together

xk_sleep_data

Key	Possible Values	Description
measurement_index	0 to 9999	Gateway internal message counter, this provides a way to correlate measurements together

xk_hardware_status_data

Hardware debugging only, not for clinical use

Key	Possible Values	Description
distance_median	N/A	Median distance calculated from high-reliability respiratory rate over the specified interval (meters)
distance_mean	N/A	Mean distance calculated from high-reliability respiratory rate over the specified interval (meters)
distance_variance	N/A	Distance variance calculated from high-reliability respiratory rate over the specified interval (meters^2)
pobc_time	0 to 144000	Minutes of the data collected for the POBC calculation
movement_average	N/A	Average relative movement measured over the specified interval (unitless)
data_cursor	N/A	The latest data index within the specified interval (unitless)
measurement_index	0 to 9999	Gateway internal message counter, this provides a way to correlate measurements together

xk_discovery_log

Hardware debugging only, not for clinical use

Key	Possible Values	Description
serial_no	N/A	The serial number of the XK unit discovered in discovery mode
rssi	-127 to 10	The current RSSI of the connection

Additional Parameters That Can be Set Via Device Properties

Key	Possible Values	Description
measurement_webhook_id	Webhook UUID	Set this property to configure a Device to only send measurement data to a single Webhook (specified by that Webhook’s ID).

Downloads & Device Support

Device	Resources
Xandar Kardian 300 Essence	Quick Start Guide | User Manual | Device Support

What is the POBC Score?

The Probability of Change in Condition (POBC) score quantifies how unusual a patient’s most recent readings are compared to their own baseline. It enables early detection of health deterioration by notifying clinicians when there is a significant change that may require attention.

Clinical Value

• Identify patients with significant changes from their personal norm
• Prioritize care based on quantified deviation severity
• Triage patients needing closer clinical assessment

The POBC score answers one question

“What are the odds my patient’s vital signs have changed over their normal?”

How It Works

Scoring is based on the previous 7 days of measurements. At least seven days of data must be collected by the XK Essence before a POBC score can be calculated. The score compares the most recent readings against the individual’s established baseline — not population averages.

Score Range

Score	Meaning	Action
-100 to -80	High probability vital signs are lower than baseline	Clinical assessment recommended
-80 to +80	Within expected variation for this patient	No action required
+80 to +100	High probability vital signs are higher than baseline	Clinical assessment recommended
Blank or 123	Insufficient data to calculate score	Continue collecting data

Direction of Change

Positive or negative POBC values describe the direction of the change:

• Respiratory POBC: -85 — 85% probability that the resting respiratory rate is lower than baseline.
• Heart rate POBC: +95 — 95% probability that the resting heart rate is higher than baseline.

POBC scores for heart rate and respiratory rate are independent and calculated separately.

Independent Validation

Clinical evidence

Xandar Kardian’s POBC Score System is independently validated to detect early clinical changes, predicting 75.6% of hospital transfers up to 7 days prior, in a validation study with 201 patients.

When the POBC Score Will Not Change

• The patient’s range of normal vital signs is already high (wide baseline)
• Insufficient data samples have been collected
• Vital signs are stable and not changing
• No clear baseline has been established (fewer than 7 days of data)
• The onset of change is very acute/sudden (e.g., pulmonary embolism, drug overdose, sudden cardiac arrest)