SEM Scanner FAQ

Section 1 SEM Scanner Model 200 Clinical Questions

How is Sub-Epidermal Moisture (SEM) affected by inflammatory markers being raised systemically by other health conditions, e.g. Sepsis / lower limb edema?

The SEM Scanner is the first FDA authorized device to objectively alert clinicians to specific areas of a patient’s body at increased risk of developing Pressure Injuries/Ulcers (PI/PU).

The device exploits differences between the dielectric constants of materials that make up tissue. Dry tissue has a low dielectric constant while water has a dielectric constant that is 20x higher. When the sensor is pressed against an area on the skin, the SEM Scanner measures the electrical capacitance of the sensor, which is affected by the moisture within the underlying skin tissue to a depth of approximately 4 mm.

If inflammatory markers are raised systemically but there is no PI/PU, for example as a result of sepsis, the Delta reading at a certain anatomical site susceptible to PI/PU and an adjacent tissue site where there is no injury would be small – because BBI’s data show the systemic conditions will cause rise in SEM readings at both sites, and hence the Delta will be normal. Likewise, in the case of a large-scale edema that is not localized, such as the legs in lymphedema, if there is no PI/PU the Delta would be small, as readings will be taken at two sites where fluid contents in tissue are similar and therefore baseline moisture levels will be high at the two sites and again, the difference between sites would be small.

How do barrier cream and agents such as protective skin sprays affect SEM readings?

The SEM Scanner readings are sensitive to changes in local tissue fluid. Moisturizers and other agents, which contain water, may affect local SEM readings on a transient basis for up to 20 minutes after application. We recommend that the SEM Scanner is used on clean and dry skin.

A publication is pending on this topic.

Any advice or information on scanning bariatric, morbidly obese patients (patients with a high body fat composition / high BMI)? Presume no evidence / contra-indication here due to the uniformity of body fat?

Our clinical data suggests that BMI is not a confounder for SEM Scanner readings. SEM values may vary in reflecting tissue fluid in skin with a higher or lower fat density.  However, because body fat is usually proportionally distributed in local scan areas around the bony prominences, the SEM delta reflects the distribution of readings performed to assess localized tissue health consistently.

What evidence do you have to support the use of the SEM Scanner?

Section 2 SEM Scanner Model 200 General Questions

What is the SEM Scanner?

The SEM Scanner, a wireless handheld device that is indicated for use as an adjunct to the standard of care when assessing patients who are at increased risk for PI/PU. The SEM Scanner is the world’s first FDA-authorized device to objectively alert clinicians to specific anatomical areas of a patient’s body at increased risk for developing pressure damage1. This data facilitates earlier, and anatomically specific interventions designed to reverse the damaging effects of pressure and shear and prevent PI/PU from breaking through the skin. Patient risk assessments are performed with the SEM Scanner before visible damage manifests at the skin surface.

Not all incipient damage will progress to a PI/PU especially when anatomically-specific interventions are applied before damage manifests at the skin’s surface.

What is included with the SEM Scanner?

The SEM Scanner is packaged with the Instructions For Use, an inductive charging mat and a power adapter for charging of the built-in rechargeable battery.

How does the SEM Scanner work?

A SEM Scanner reading is obtained by placing the integrated sensor against the patient’s skin. When the sensor is applied to the skin with sufficient pressure – as indicated by the pressure indicator – a SEM Scanner reading is displayed on the screen. The sensor must be in complete contact with the skin to acquire a proper reading. The SEM Scanner displays the recent SEM Value and, after the third reading, a delta value is displayed, namely the difference between the lowest and highest SEM Values from a series of readings performed for an anatomical location (e.g., heels/sacrum). The readings can be taken during routine clinical care such as when visual skin assessments are undertaken or hygiene care procedures.

What is the SEM Scanner measuring?

The SEM Scanner’s values change in proportion to the dielectric constant of the material in contact with the sensor. Skin and tissue in direct contact with the sensor changes the displayed value according to the level of skin and tissue’s sub-epidermal moisture (SEM).  SEM has been studied as an indicator of localized edema characteristic of pressure tissue damage. The SEM Scanner’s values are affected by changes in moisture content of the dermis to approximately 4 mm. The SEM value is used to assess the absence or presence of tissue damage. Recorded SEM Scanner values range from 0.3 to 3.9 within the Scanner’s scale of 0.0-7.0.

Which of my patients might benefit from the SEM Scanner?

All adult patients who are at risk for developing PI/PU.

Who can use the SEM Scanner?

The SEM Scanner is designed for use by clinical professionals in the clinical setting (by prescription only). The device may be used by clinical professionals such as nurses, nurse practitioners, healthcare assistants and/or clinical professionals specializing in wound care.

How does the SEM Scanner add to current standard of care?

Current standard of care generally includes some combination of visual skin assessment and one or more PI/PU risk assessment tools such as the Braden, Waterlow, or Norton scales. The SEM Scanner is an adjunct to standard of care assessments with an objective alert of specific anatomical areas of a patient’s body at increased risk of PI/PU.

Does the SEM scanner cause pain/discomfort to the patient?

No. Other than feeling the sensor press against the skin, our clinical studies and use in real world case studies have demonstrated that the device did not cause pain or discomfort to the patients.

Are there patients on whom the SEM Scanner should not be used?

Yes. The SEM Scanner cannot be used on patients with broken skin over the anatomy in question. The device is not cleared for use on pediatric patients.

Is there training required to operate the SEM Scanner?

Yes. The Company provides comprehensive device training. Training should be undertaken before first use of the device.  The Instructions for Use should be read and understood before first use to ensure correct operation of the device, and information on warnings and precautions.

How do you recommend the SEM Scanner be cleaned?

Yes. Refer to the Instructions For Use for detailed cleaning and disinfection steps.

How many hours of battery life does the device have?

When fully charged, the battery provides approximately three hours of SEM Scanner accumulated operation. Place the device on the charging mat for at least six hours to completely charge the battery.

1. Okonkwo H., et al (2020). A blinded clinical study using a subepidermal moisture biocapacitance device for early detection of pressure injuries. Wound Repair Regen, (online) 1-11. Available at: https://doi.org/10.1111/wrr.12790 (January 2020)

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