What are Type I, Type II, Type III sleep monitors?

Learn definitions of the types of sleep studies devices according to CMS (the Center for Medicare & Medicaid Services) and AASM (the American Academy of Sleep Medicine). CleveMed currently offers four sleep monitors that fall within these defined categories for the purposes of sleep (Type I – Sapphire PSG, Type II – Crystal Monitor, and Type III –SleepScout, SleepView for home sleep testing). You can also read the new home sleep testing classification system (Journal of Clinical Sleep Medicine), and find the clinical guidelines for the use of unattended portable sleep monitors (from the Journal of Clinical Sleep Medicine) with the “Portable Monitoring Decision Tree“.

Type I

Attended studies (sleep studies that are performed with the oversight of a sleep technologist) with full sleep staging (sleep staging monitors the transition through the sleep stages, traditionally with the use of EEG electrodes that monitor the brain). Type I devices must include the following channels:

      • EEG
      • EOG
      • ECG/Heart rate
      • Chin EMG
      • Limb EMG
      • Respiratory effort at thorax and abdomen
      • Air Flow from nasal canula thermistor and/or X-Flow (AASM recommends RIP technology
      • Pulse Oximetry
      • Additional channels for CPAP/BiPap levels, CO2, pH, pressure, etc.

(CPT #


    • Baseline PSG,


    • MSLT,



Type II

Home sleep test (HST) with Type II portable monitor, unattended (sleep studies that are performed without the oversight of a sleep technologist), with a minimum of 7 channels. Type II devices must include the following channels:

      • EEG
      • EOG
      • ECG/heart rate
      • EMG
      • Airflow
      • Respiratory effort
      • Oxygen saturation




Type III

Home sleep test (HST) with Type III portable monitor, unattended with a minimum of 4 channels. Type III devices must include the following channels:

      • 2 respiratory movement/airflow
      • 1 ECG/heart rate
      • 1 oxygen saturation



    • , CPT



Type IV

Home sleep test (HST) with Type IV portable monitor, unattended; minimum of 3 channels. Type IV devices must allow channels that allow direct calculation of an AHI or RDI as the result of measuring airflow or thoracoabdominal movement. Alternatively devices that record other information to derive AHI or RDI must be approved by CMS through the review of published peer-reviewed medical literature. (HCPCS #G0400)

To determine exact reimbursement amounts for your state, click here. Enter the appropriate code from the list above and select your state to find reimbursement amounts.

Type I

Monitoring devices perform in-laboratory, technician-attended, overnight polysomnography (PSG) and are discussed separately. (CPT #95810 Baseline PSG Study, CPT #95805 MSLT Study and CPT #95811 Titration Study (CPAP))

Type II

Monitoring devices can perform full PSG outside of the laboratory. The major difference from type 1 devices is that a technologist is not present. These devices are called comprehensive portable devices. (CPT #95807)

Type III

Monitoring devices do not record the signals needed to determine sleep stages or sleep disruption. Typically channels include:

      • Four physiologic variables are measured including:
        • Two respiratory variables (eg, respiratory movement and airflow)
        • Cardiac variable (eg, heart rate or an electrocardiogram)
        • Arterial oxygen saturation
      • Some devices may have other signals including a monitor to record snoring, detect light, or a means to determine the body position.

(CPT #



Type IV

These devices are called continuous single or dual bioparameter devices. Monitoring devices record one or two variables and can be used without a technician. Typically channels include:

  • Arterial oxygen saturation
  • Airflow

(As seen in Sleep Review – The Journal for Sleep Specialists)

A new classification system detailing the type of signals measured by home sleep testing devices for diagnosing obstructive sleep apnea (OSA) appears in the latest issue of the Journal of Clinical Sleep Medicine.

The proposed system categorizes home sleep testing devices, called out-of-center (OOC) testing devices in the paper, based on measurements of Sleep, Cardiovascular, Oximetry, Position, Effort, and Respiratory (SCOPER) parameters. Criteria for evaluating the devices are also presented, based on pre-test and post-test probabilities.

The first widely used classification system for describing sleep testing devices was published by the American Academy of Sleep Medicine (AASM) in 1994. “There’s been a plethora of testing devices developed since then that do not fit well within the original classification scheme,” said Nancy Collop, MD, president of the AASM and lead author of the review article. “The previously accepted method of classification has become unsuitable. A new classification system, SCOPER, is being proposed in this paper.

Last year, the AASM board commissioned a task force to determine a more specific and inclusive method of classifying and evaluating sleep testing devices other than polysomnography (PSG) used as aids in the diagnosis of obstructive sleep apnea (OSA) in the OOC setting. The scope of the commission’s work was limited to classification and evaluation of performance characteristics, and not the technology’s use in practice guidelines, accreditation standards, or management principles.

Collop said the paper is meant to be the first step in a comprehensive process to evaluate and subsequently make recommendations on how to use home sleep testing devices in an outpatient population. The next paper is expected to address the important issues of determining pretest probability, interpreting study results, and developing testing algorithms and treatment decisions.

CleveMed’s home sleep monitors meet the SCOPER guidelines with the following scores:

SleepView SCOPER Scores
Sleep – 3*
Cardiovascular – 4
Oximetry – 1
Position – 2
Effort – 2
Respiration – 1
*(with web portal)

SleepScout SCOPER Scores
Sleep – 2
Cardiovascular – 3
Oximetry – 1
Position – 2
Effort – 1
Respiration – 1

(The following excerpts were taken directly from the Journal of Clinical Sleep Medicine, Vol. 3, No. 7, 2007)


    1. Indications for Portable Monitoring

      1.1. Portable monitoring (PM) for the diagnosis of Obstructive Sleep Apnea (OSA) should be performed only in conjuction with a comprehensive sleep evaluation. Clinical sleep evaluations using PM must be supervised by a practitioner with board certification in sleep medicine or an individual who fulfills the eligibility criteria for the sleep medicine certification examination. In the absence of a comprehensive sleep evaluation, there is no indication for the use of PM.

      1.2. Provided that the recommendations of 1.1 have been satisfied, PM may be used as an alternative to polysomnography (PSG) for the diagnosis of OSA in patients with a high pretest probability of moderate to severe OSA. PM should not be used in the patient groups described in 1.2.1., 1.2.2., and 1.2.3. (those with comorbidities, other sleep disorders or for screening).

        • 1.2.1. PM is not appropriate for the diagnosis of OSA in patients with significant comorbid medical conditions that may degrade the accuracy of PM, including, but not limited to, moderate to severe pulmonary disease, neuromuscular disease or congestive heart failure. JCSM Journal of Clinical Sleep Medicine, Vol. 3, No. 7, 2007 Recommendations
        • 1.2.2. PM is not appropriate for the diagnostic evaluation of OSA in patients suspected of having other sleep disorders, including central sleep apnea, periodic limb movement disorder (PLMD), insomnia, parasomnias, circadian rhythm disorders or narcolepsy.
        1.2.3. PM is not appropriate for general screening of asymptomatic populations.

      1.3. PM may be indicated for the diagnosis of OSA in patients for whom in-laboratory PSG is not possible by virtue of immobility, safety or critical illness.

      1.4. PM may be indicated to monitor the response to non-CPAP treatments for obstructive sleep apnea, including oral appliances, upper airway surgery and weight loss.

    1. Technology for Portable Monitors

      2.1. At a minimum, the PMs must record airflow, respiratory effort and blood oxygenation. The type of biosensors used to monitor these parameters for in-laboratory PSG are recommended for use in PMs.

      2.2. The sensor to detect apnea is an oronasal thermal sensor and to detect hypopnea is a nasal pressure transducer. Ideally, PMs should use both sensor types.

      2.3. Ideally, the sensor for indentification of respiratory effort is either calibrated or uncalibrated inductance plethysmography.

  1. Methodology for Portable Monitoring

    3.1. PM testing should be performed under the auspices of an AASM accredited comprehensive sleep medicine program with policies and procedures for sensor application, scoring and interpretation of PM. A quality/performance improvement program for PM including inter-scorer reliability must be in place to assure accuracy and reliability.

    3.2. An experienced sleep technician, sleep technologist or appropriately trained healthcare practitioner must perform the application of PM sensors or directly educate the patient in the correct application of sensors.

    3.3. PM devices must allow for the display of raw data for manual scoring or editing of automated scoring by a trained and qualified sleep technician/technologist. Evaluation of PM data must include review of the raw data by a board certified sleep specialist or an individual who fulfills the eligibity criteria for the sleep medicine certification examination.

    3.4. Scoring criteria should be consistent with the current published AASM standards for scoring of apneas and hypopneas.

    3.5. Due to the known rate of false negative PM tests, in-laboratory polysomnography should be performed in cases where PM is technically inadequate or fails to establish the diagnosis of OSA in patients with a high pretest probability.

    3.6. A follow-up visit with a physician or other appropriately trained and supervised health care provider should be performed on all patients undergoing PM to discuss the results of the test.

    3.7. Unattended PM can be used within the parameters specified above in the patient’s home.


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