• Measures Resting Energy Expenditure (REE/RMR)
  • Determines caloric requirements
  • CPT code #94690
  • FDA cleared
  • Can be operated by any office staff
  • Unique printout to aid teaching

The REEVUE measures the oxygen that the body consumes. Using this measurement it calculates a patient’s Resting Energy Expenditure (REE), commonly referred to as a Resting Metabolic Rate (RMR). Physicians can screen for abnormally low metabolic rates and pinpoint the precise caloric intake required for weight loss, maintenance, or weight gain.  Applications include nutritional assessments required to treat obesity as well as obesity related diseases such as metabolic syndrome, sleep disorders, diabetes, and thyroid disorders.   Under strict laboratory protocol, the ReeVue can be used to measure basal metabolic rate (BMR).  To download a ReeVue product brochure, click here.

Why Choose ReeVue?

Direct Oxygen Measurement

ReeVue by KORR directly measures the concentration of oxygen breathed out by each patient.  The patient merely breathes through a simple mouthpiece as all the exhaled air is collected and analyzed.  Because there is a direct correlation between oxygen consumed and calories burned (4.813 calories for every milliliter of oxygen consumed), an accurate measurement of oxygen consumption is an effective measurement of calorie consumption.

Mixing chamber Technology

A mixing chamber is considered the “Gold Standard” for Indirect Calorimetry (more commonly referred to as a Metabolic Measurement.) In the past, this system has been complicated and expensive, making it only practical for ICU’s and research departments. KORR advancements in technology make this method feasible for the typical practitioner.

Self Calibrating

Adjustments for barometric pressure, temperature, and humidity are key to an accurate VO2 measurement.  The ReeVue measures these parameters during each routine calibration cycle, then automatically compensates to standard (STPD) conditions.


Other Indirect Calorimeters require the patient to draw both their inhalation and exhalation through the measurement device located at the patient’s mouth.  The air they breathe in will pass through the same mechanism as countless patients before them.  KORR uses a one-way valve in the disposable MetaBreather mouthpiece.  This draws in fresh room air with each inspiratory breath and eliminates concerns about cross contamination.  The disposable is thrown away and there is no need to clean equipment between each patient.


The ReeVue has a simple user interface that assists the operator from start to finish.  No training or certification is required.  It does not require a computer or software, and even the printer is optional.  Everything you need is at your fingertips!

Reimbursable & Accurate

The ReeVue performs an oxygen uptake test, which is CPT code #94690.

ReeVue has been independently validated at the University of Southern California and Georgia State Univiersity.  To view those results, click here.

Pre-Test Requirement

It is desirable to measure a person’s metabolic rate at a true resting level. To ensure one is at rest, we recommend the following preparation:

  1. Fast for 4 hours prior to testing.
  2. Avoid strenuous exercise prior to testing.
  3. Refrain from stimulants such as caffeine or nicotine.
  4. Relax and avoid distractions while testing.
  5. Keep lips sealed lightly around the mouthpiece. It is important that all the air breathed out is analyzed by the ReeVue™.
woman doing reevue test on couch next to reevue machine
woman on chair

Conduct a Test

  1. Turn on the ReeVue™ and wait while it automatically calibrates. Remove any hose or filter during calibration.  The machine will indicate when calibration is complete.
  2. Expand the MetaBreather hose to its full length (5 feet) and connect it to the ReeVue™. Be sure to use only a KORR™ manufactured MetaBreather as use of any other breathing device will not insure accuracy and will void your KORR™ factory warranty.
  3. Have the patient place the nose clip on his nose and the mouthpiece in his mouth, using his lips to seal around the edges. The patient should be relaxed and breathe normally.
  4. After approximately 10 minutes, the ReeVue™ will end the test and prompt the tester to enter in patient data to compare patient results to averages. The results can then be printed out.

Video Demonstration:

The Print Out

Click the button below to view/download the print out

Download/View PDF

CPT Codes

Indirect calorimetry is CPT coded and is covered by Medicare and most insurance providers.  If you have any questions about insurance coverage, contact insurance providers directly.

CPT CodeDescriptionMedicare National
Fee Limit
94690Oxygen uptake, expired gas analysis, rest, indirect$53.62

Diagnosis Codes – Weight Loss

CPT codes must be accompanied by an appropriate diagnosis code (ICD-10).

Weight Management:

Medicare Nationally Covered Indications currently reads: “services performed in connection with the treatment of obesity are covered by Medicare when such services are an integral and necessary part of a course of treatment for diseases such as hypothyroidism, Cushing’s disease, hypothalamic lesions, cardiovascular diseases, respiratory diseases, diabetes, and hypertension.”

The AMA* cites that diagnoses codes supporting the medical necessity of Indirect Calorimetry include:

  • E88.81  Metabolic Syndrome
  • E88.9  Metabolic Disorder, Unspecified
  • G47.00 – G47.9  Sleep Disturbances
  • R06.02  Shortness of Breath
  • Z79.899  Long Term Use of Other Medications
  • R94.8  Abnormal results of function studies of other organs and systems (High or low metabolic rate)

Diagnosis Codes – Nutrition

CPT codes must be accompanied by an appropriate diagnosis code (ICD-10).

Nutritional Assessments

  • R94.8  High or Low Metabolic Rate.  Abnormal results of function studies of other organs and systems

Secondary to:

  • Z71.3 Dietary surveillance and counseling

Behavioral Therapy

  • G0447 Intesive Behavioral Therapy for Obesity (see pdf below for details)

G0447 Code paper

Download G0447 Code Paper

*AMA CPT / ADA CDT Copyright Statement

CPT only copyright 2002 – 2013 American Medical Association. All Rights Reserved. CPT is a registered trademark of the American Medical Association. Applicable FARS/DFARS Apply to Government Use. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.

Resting Metabolic Rate (RMR) is a VITAL SIGN for treating Overweight & Obese Patients

doctor weighing the patientIn 2006, the Northwestern Comprehensive Center on Obesity tested the RMR of 76 of their female patients. 17% of them would not have lost weight on the standard “1200 calorie a day” diet. In fact, they probably would have gained from 5 to 32 pounds in one year. Yet there were no other indicators that set them apart from those who could lose weight on that same diet.

Is it any wonder patients are frustrated?

For more information on the Northwestern Study, view this video

So what can a doctor do?


A simple 10 minute RMR test can accurately pinpoint how many calories a patient needs to consume to lose weight.


Showing a patient the results of their own metabolic test gives you the opportunity to teach solid scientific principles within the context of their own bodies. Studies show that this is the ideal circumstance to elicit behavior change.


Armed with a proper medical assessment, your patient is now ready to be referred to a weight loss expert. You may have an expert program set up within your practice. Or you may want to refer to a Bariatrician or community based program. Your KORR representative will be happy to assist you with this next step.

O₂ Sensor
TypeGalvanic Fuel Cell
Accuracy±0.2% O₂
Resolution0 to 30% O₂
Average Sensor Life24 months
Air Flow Sensor
TypeFixed-orifice Differential Pressure Pneumotach
Accuracy±2% of reading
Resolution0.01 LPM
Range-40 to 150 LPM
Breath Rate5 to 40 breaths/minute
Tidal Volume200 to 3000 ml
Physical Dimensions
Size12” x 9” x 4”
Weight5.75 lbs (2.6 kgs)
Average Difference24.7 kcal/day (-1.45%)
Standard Deviation of Difference57.1 kcal/day (2.85% of reading)
0.975 (r=987)

ReeVue Frequently Asked Questions

How long does this test take?
The test takes approximately 10 minutes.
How many tests can you do on the machine?
The ReeVue™ will perform an unlimited number of tests.
Can the disposable hose be used more than once?
The disposable hose (the METABREATHER™) is for single patient use only. It cannot be effectively cleaned between patients and the valves within the mouthpiece will not maintain accuracy through multiple tests.
Is certification required to operate the machine?
No certification is required. With its simple one button operation, anyone can be trained to operate the ReeVue™ in just minutes.
What kind of warranty do the products come with?
All KORR™ products come with a full 2 year warranty which includes all parts and labor. Routine maintenance is not covered under warranty. A renewable warranty is available to purchase for subsequent years.
What happens if the machine needs any maintenance?
All maintenance and repairs are performed at KORR™ Medical's Service Center in Salt Lake City, Utah. The ReeVue requires oxygen sensor replacement and recalibration every 20-24 months, regardless of usage.

For more information on metabolic rate testing, click the link below:

Understanding RMR
Metabolic Rate Testing

Why KORR? Here is what our customers are saying….

The American Dietetic Association (ADA) Evidence Analysis Library recommends the use of indirect calorimetry to measure RMR for overweight and obese patients… When choosing an indirect calorimeter, the ADA Evidence Analysis Library recommends reviewing the safety features, ease of use, accuracy, precision, reliability, durability, and the machine’s service/maintenance plan. At the Northwestern Comprehensive Center on Obesity, we use the ReeVue Indirect Calorimeter by KORR Medical Technologies.

I have been using the ReeVue for about 5 years and have found it to be an invaluable piece of diagnostic equipment for my bariatric practice. With all of my medical weight loss patients, I perform the test at their initial evaluation.  I am then able to guide patients as to where they need to be calorically to bring about weight loss. If/when patients plateau, I can repeat the ReeVue to assess their calorie needs. Likewise, the ReeVue can be used to determine calorie needs for weight maintenance.

In addition it is useful for those bariatric surgical patients that are not losing weight post-surgically or have regained weight post-surgery. I am able to demonstrate to them where they need to be to bring about a healthy weight loss.

Click here to read Dr Basket’s interview in it’s entirety.

In our medical weight loss clinic, we use the ReeVue Indirect Calorimeter. We use the RMR to set a diet based on how many calories patients burn at rest. The test takes about 10 minutes, the clients feel like they are getting a really good assessment, and they are all really interested in what their metabolic rate is. Testing someone’s metabolic rate is key to finding those few people who lie outside the norm so you know where to set their caloric limits.

See Dr. Larsen’s interview here

Metabolic measurement is the key component we use for initial diagnostic testing to evaluate and treat overweight and obese people. It provides scientific principles to interact with patients and get them thinking about calories and metabolic rates. Therefore, it helps them be more successful short term, and provides guidelines for maintenance long term. The ReeVue is a great device.

The ReeVue metabolic test revealed I could eat 2400 calories and still lose weight. I really had been starving my body! I bumped up my calories, kept working out, and it was like magic – in one month my weight dropped from 314 lbs to 292 lbs! I felt great and wasn’t hungry any more.