SpMet is a breakthrough measurement that allows clinicians to noninvasively and continuously monitor levels of methaemoglobin in the blood




Elevated Methaemoglobin

  • > Methaemoglobin is a form of haemoglobin that is less able to bind to oxygen1
  • > Methaemoglobinemia is a condition where there are elevated levels of methaemoglobin in the blood, which impairs oxygen delivery to tissues2
  • > The administration of many drugs commonly used in hospitals–such as lidocaine, benzocaine, dapsone, and nitrates–may result in acquired methaemoglobinemia2

Medications that may increase methaemoglobin levels
in the blood


Measuring Methaemoglobin with SpMet

  • > Masimo pulse CO-oximetry provides a method to noninvasively and continuously measure methaemoglobin in the blood
  • > Measurements are taken by placing a sensor on a patient, usually on the fingertip for adults
  • > Accuracy range 1-15% with +/- 1% ARMS3

rainbow SET Technology Platform

Masimo rainbow SET is a noninvasive monitoring platform featuring Masimo SET® Measure-through Motion and Low Perfusion pulse oximetry with the option to measure multiple additional parameters.

  • > Oxygen Saturation (SpO2)
  • > Pulse Rate (PR)
  • > Perfusion Index (Pi)
  • > Pleth Variability Index (PVi®)
  • > Oxygen Content (SpOC)
  • > Oxygen Reserve Index (ORi)
  • > Total Haemoglobin (SpHb®)
  • > Methaemoglobin (SpMet)
  • > Carboxyhaemoglobin (SpCO®)
  • > Acoustic Respiration Rate (RRa®)
  • > Respiration Rate from the Pleth (RRp)

Masimo Radical-7 upgraded with RRa


  • 1 Miller’s Anesthesia 8th Edition. 2015.
  • 2 AshBernal RA et al. Medicine. 2004 83:265273.
  • 3 ARMS accuracy is a statistical calculation of the difference between device measurements and reference measurements. Approximately two-thirds of the device measurements fell within +/- ARMS of the reference measurements in a controlled study.


  • > Click here for available SpMet studies.
  • > Click here to receive more information about noninvasive and continuous SpMet.

SpMet monitoring with Masimo devices is not intended to replace laboratory blood testing. Blood samples should be analysed by laboratory instruments prior to clinical decision making.

For professional use. See instructions for use for full prescribing information, including indications, contraindications, warnings, and precautions.