SpMet is a breakthrough measurement that allows clinicians to noninvasively and continuously monitor levels of methemoglobin in the blood—a form of hemoglobin that is incapable of carrying oxygen


Elevated Methemoglobemia

  • > The administration of many drugs commonly used in hospitals–such as lidocaine, benzocaine, dapsone, and nitrates–may result in acquired methemoglobinemia which reduces oxygen delivery to tissues.
  • > While methemoglobinemia can occur in all care areas and patients, it is often unrecognized and undiagnosed.
  • > If not identified and treated, it can result in
    avoidable injury or death.

Medications Known to Increase Methemoglobin Levels in the Blood:
Benzocaine, Cetacaine, Chloroquine, Dapsone, EMLA topical, Flutamide, Lidocaine, Metoclopramide, Nitrates, Nitric oxide, Nitroglycerin, Nitroprusside, Nitrous oxide, Phenazopyridine (Pyridium), Prilocaine, Primaquine, Riluzole, Silver nitrate, Sodium nitrate, Sulfonamides.

Prevalence of Methemoglobinemia

Number of
Methemoglobinemia Cases
Patient Age Care Areas Fatalities
(2.5 cases per hospital per month)
4 days to 86 years Surgery, intensive care, outpatient clinics, pediatrics,
emergency department, cardiac cath lab
1 fatality
3 near fatalities

Results from a retrospective study at two Johns Hopkins Hospitals over a 28-month period, using laboratory CO-Oximeter results, and patient electronic medical records.1

"Acquired methemoglobinemia is fairly common and causes morbidity and mortality in both the inpatient and outpatient settings. Acquired methemoglobinemia is often unrecognized and thus untreated."

Dr. Rachel Ash-Bernal
and other researchers at Johns Hopkins Hospital


  • 1 Ash-Bernal RA et al. Medicine. 2004;83:265-273.

Upgradable 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 blood constituents and physiologic parameters.

  • > Oxygen Saturation (SpO2)
  • > Pulse Rate (PR)
  • > Perfusion Index (PI)
  • > Total Hemoglobin
  • > Oxygen Content (SpOC™)
  • > Pleth Variability Index (PVI®)
  • > Methemoglobin (SpMet®)
  • > Carboxyhemoglobin (SpCO®)
  • > Acoustic Respiration Rate (RRa®)

Masimo Radical-7 upgraded with RRa

The upgradeable rainbow® platform lets you choose the rainbow® measurements that are right for you now and be confident that your investment in patient safety won’t become obsolete tomorrow.


Information Sheet
Information Sheet Reimbursement for Quantitative, transcutaneous: Total Hemoglobin, Carboxyhemoglobin and Methemoglobin.

SpMet monitoring with Radical-7 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.