Z-Track Precision: When Close is Not Good Enough

Z-Track Blog

Z-Track Virtually Eliminates Zero Drift

The Importance of Precision in Medical Diagnostics

To properly diagnose, medical diagnostic equipment must be accurate – very accurate. Often times the difference between an effective and ineffective treatment plan depends on the precision of the diagnosis. A small difference in a measurement can alter the dosage or even the type of medication a patient should take. This is true for many types of medical tests including blood work, MRIs, temperature measurements and lung capacity.

With increases in air pollution, higher smoking prevalence and aging populations, chronic lung disease is on the rise. Illnesses such as chronic obstructive pulmonary disease (COPD) and asthma are affecting a larger portion of the world’s population. A spirometer is a vital tool to diagnose and manage these and other lung diseases by measuring the lung capacity and volume under various conditions.  

Spirometers rely on differential pressure sensors to accurately diagnose a patient’s lungs. The sensors measure air flow when you inhale and exhale to provide accurate data. With each breath, the spirometry equipment re-zeroes the sensor to capture the next reading. The doctor then uses this data to diagnose the patient and devise a treatment plan. However, during the diagnostic cycle, which can last up to 10 seconds or more, the spirometer can ‘drift’ from its zero position and lead to less accurate readings. Ensuring an accurate reading is paramount for the best patient care.

Z-TrackTM Technology

Superior Sensor Technology’s proprietary NimbleSenseTM architecture combines processing intelligence with signal path integration and intelligent algorithms to create modular building blocks that are easily selectable to support a wide array of applications. To ensure the utmost accuracy in medical devices, the company has developed its proprietary Z-Track technology that virtually eliminates zero drift. This provides greater accuracy to devices such as spirometers, resulting in more effective diagnosis and better treatment plans.

Figure 1:  Z-Track Output Graph vs. Traditional Pressure Sensors

Z-Track Graph

Z-Track virtually eliminates zero errors to ensure the most accurate spirometry readings in the industry. As you can see from Figure 1, Z-Track maintains minimal zero-point deviation with results that are consistent regardless of elapsed time. When combined with the Superior’s position insensitivity capability, the company’s differential pressure sensors provide the most accurate readings for all types of spirometry equipment including handheld and desktop units. Not only are you certain that the device has virtually eliminated all zero errors, but you can be sure of accurate readings regardless of how the spirometer is positioned or used.


Z-Track technology is currently available on the SP Series of differential pressure sensors, the SP110, SP160 and SP210. The SP Series sensors have the following attributes:

  • Very fast data rate of 2 ms
  • Selectable bandwidth filter from 10 Hz to 250 Hz
  • 16-bit resolution
  • Ultra low noise, 19-bit effective resolution
  • Best in class position insensitivity (SP210 model)
  • Total Error Band (TEB) less than 0.15% FSS
  • Accuracy range better than 0.10%
  • Multi-Range technology support with 4 calibrated ranges per device:
    • SP110 supports 4 pressure ranges  ±250 Pa to ±2.5K Pa    (±1” H2O to ±10” H2O)
    • SP160 supports 4 pressure ranges  ±5K Pa to ±40K Pa      (±20” H2O to ±160” H2O)
    • SP210 supports 4 pressure ranges  ±250 Pa to ±2.5K Pa    (±1” H2O to ±10” H2O)

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