Methemoglobin (SpMet®)

Elevated Methemoglobin

Elevated Methemoglobin

  • Methemoglobin is a form of hemoglobin that is less able to bind to oxygen1
  • Methemoglobinemia is a condition where there are elevated levels of methemoglobin 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 methemoglobinemia2

Measuring Methemoglobin with SpMet

Measuring Methemoglobin with SpMet

  • Masimo pulse CO-oximetry provides a method to noninvasively and continuously measure methemoglobin 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
Masimo - SpMet - rainbow SET Technology Platform

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™)
  • Total Hemoglobin (SpHb®)
  • Methemoglobin (SpMet)
  • Carboxyhemoglobin (SpCO®)
  • Acoustic Respiration Rate (RRa®)


  1. 1.

    Miller’s Anesthesia 8th Edition. 2015.

  2. 2.

    AshBernal RA et al. Medicine. 2004 83:265273.

  3. 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.


Masimo - Thumbnail of SpMet Studies

Follow the link for available SpMet studies.

Masimo - Thumbnail of Noninvasive and Continuous SpMet
Follow the link to receive more information about Noninvasive and Continuous SpMet.
Product Information, SpMet

Product Information

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

Caution: Federal (USA) law restricts this device to sale by or on the order of a physician. See instructions for use for full prescribing information, including indications, contraindications, warnings, and precautions.