interpreting test results
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interpreting unexpected results

If you receive unexpected results, please follow this troubleshooting procedure (be sure to print out a report for your reference):

1. Confirm proper data input and settings.

a. Correct sex input (i.e. male versus female).
b. Proper measurement units for height (i.e. inches versus centimeters).
c. Proper measurement units for weight (i.e. pounds versus kilograms).
d. Accurate height (i.e. inches versus feet; enter "69.5" inches for a patient that is 5 feet 9.5 inches tall).

2. Confirm that the patient observed the pre-test protocol.

Did your patient observe the following guidelines?

a. No alcohol consumption within 24 hours of taking the test.
b. No exercise, caffeine or food for four hours prior to taking the test.
c. Drink plenty of water in the 24 hour period prior to testing to maintain normal hydration.
The conductivity of an individual's fat-free mass depends on its water content. Therefore, hydration levels will affect resistance readings. Alcohol can cause temporary dehydration. Caffeine and some medications including diuretics can also cause temporary dehydration.

Note: Patient hydration can be reviewed by checking the total body water. Normal hydration levels indicate that fat-free mass contains approximately 69% to 74% water. Total body water reading equal to less than 69% of the patient's fat-free mass may indicate dehydration. This information can provide a useful explanation for a high fat mass reading.

For more information, see effects of hydration.

3. Check for proper electrode placement.

  Two pairs of sensor pads are placed on the patient - one on the right wrist and hand and the other on the right foot and ankle.

The wrist pad is placed on a line connecting and halfway between the prominent wrist bones (heads of radius and ulna). The tab faces outward away from the body and is directly inline with the prominent outer wrist bone (head of radius).      

The hand pad is squarely placed with the edge of the pad about one-half inch above the knuckle line toward the middle of the hand. The tab faces outward from the body.

The ankle pad is placed at the crest of the ankle on a line and halfway between the protuberances at the ankle on the outside (lateral malleolus) and on the inside (medial malleolus). The tab faces outward from the body.

The foot pad is placed squarely with the edge approximately one inch above the toe line, toward the middle of the foot. The tab faces outward from the body.

see photo
  •  Remember: Red clips closest to the heart.
  •  Remember: All measurements should be performed on the RIGHT side of the body.

For more information, see placing the sensor pads.

4. Check for good electrode-to-skin adherence.

  Proper electrode-to-skin adherence means that at least 75% of the electrode has contact with the patient's skin. For patients with a large amount of body hair, the use of electrode gel and/or tape may be required to ensure proper contact.

If one or more of the sensor pads have poor contact with the skin, resistance to the injected current may result in a high body fat reading. With good electrode-to-skin contact, by using the four site electrode technique the impedance of the sensor pad contact with the skin does NOT affect the measurement of total body impedance.

5. Check for proper sensor cable hookup.

  The red clips should be attached to the pads at the wrist and ankle joints. The black clips should be attached to the pads above the knuckles and toes. If one or both sets of cable clips are attached in reverse order high body fat results may occur.

  •  Remember: "Red clips closest to the heart."

6. Check for proper patient test position.

a.  Patient is lying down, face up in supine position.
b.  Patient is relaxed with head back.
c.  Hands are at least six inches from sides, palms down. The upper inner arm should not be touching the torso. If necessary, increase the distance between the arm and body.
d.  Feet are twelve to eighteen inches apart. For heavy set or overweight individuals, the feet need to be far enough apart so that the upper thighs do not touch each other.
e.  Right ankle and wrist are exposed. Nylon hosiery is removed.
The regression equations in the analyzers were developed using the same body position for all patients. Deviations from this position may change the normal path of the current flow through the body. Bioimpedance tests conducted with the patient standing, sitting, arms on the chest, legs crossed or close together, may lead to erroneous body fat results, both high and low.

For more information, see test position, effects of patient position.

7. Equipment.

  If all the above causes have been ruled out and consistently high or low body fat results still occur, then the unit or cable set may need servicing. Please contact Technical Support.
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