people of the world

Periodic Paralysis News Desk

Resources for the Periodic Paralysis Community since 1995

Cardy Potassium Meter Instructions

The Cardy Meter is designed for use with agricultural animals and soil samples. It is not intended for use on human saliva. However, we are attempting to prove that it will work to help us know our potassium levels and assist in the management of Periodic Paralysis. In order for the test results to be trustworthy, the patient, or someone assisting the patient, must have generous determination and much, much patience to do the required calibration and testing procedures.

IT IS NOT SIMPLE OR EASY, BUT DOES GET EASIER WITH PRACTICE.

The required procedures are very tedious and cannot be done without gentle, coordinated, controlled fingers. Therefore each patient using the Cardy Meter will need another person they can count on to take over when fingers are too weak or non functional to do the procedures or if you don’t seem to have the aptitude for doing such procedures.

Sensor holes on Cardy K+ Meter

Figure 1: Sensor holes on Cardy K+ Meter

WARNINGS:
Correct procedures must be followed in order to produce trustworthy test results with your meter. Do not flood the sensor area with too much solution. Overflow will damage or destroy, your meter. Once you get your test result, you must go through a calculation procedure and a test result lookup on a conversion chart. Only then will you see a test result that looks like what you see on your blood serum lab report.

Hold the solution bottles straight up and over the sensor holes

Figure 2: Applying the solution

HOLD SOLUTION BOTTLES STRAIGHT UP AND OVER THE SENSOR HOLES – not sideways or leaning (see figure 2). DO NOT SQUIRT THE SOLUTIONS! DROP ONLY 1 TO 2 DROPS ON EACH HOLE!

Cardy Meter, tweezers, small screwdriver, tissues, scissors, 3 solution bottles and calculator

Figure 3: Equipment needed to calibrate and use Cardy K+ Meter

Getting Ready to Test with your Cardy Meter:

You will need the three small blue bottles of (1) De-ionized Water (DW); (2) Control Solution # 20 (CS-20); (3) Control Solution # 15 (CS-15); roll of test strip and small blue tongs that come with your meter. Additional items to gather include some small scissors, a roll of toilet tissue, a small calculator and very gentle, controlled fingers finish your preparation items (see figure 3). All of this, along with your Cardy Meter can be kept in a small insulated children’s lunch bag or other such container. This makes it easy to store and transport your meter and supplies.

Calibrating your CARDY METER

ONCE A MONTH you will need to do the following more extensive calibration of your Cardy meter. Between monthly calibrations, a *briefer calibration procedure is used prior to each potassium test.

Monthly Calibration Procedure:

(**May require several repeats until meter holds calibration)

Turn your Cardy Meter on with the switch on the left top of the meter (figure 4). Lift the cover exposing the sensor.

Switching the Cardy Meter on using the wheel at the top left of machine

Figure 4: Switching the Cardy Meter on.

  1. Clean your meter’s sensor by dropping 2 drops of DW directly on each large and small circular holes in the top of the meter sensor plate. Tear off and wad up about 3 sheets off the toilet tissue. Use the tissue wad to gently dab and blot the sensor until the meter readout says “0“. You may need to use another clean wad to totally dry the sensor down to “0”.
  2. Calibrate to a Standard “20” readout. Cut off a small ½ inch piece of the test strip and cover both of the sensor holes with it. Drop 2 drops from the standard CS-20 bottle on the test strip. Watch the readout. If it does not read “20” use the standard adjustment dial at the right top and very gently (with the tip of your fingernail) adjust the reading to “20” (figure 5).
    Calibrating to standard '20' with wheel at top right of Cardi Meter

    Figure 5: Calibrating to Standard ‘20’

  3. Repeat step 1 to clean your meter sensor back down to “0”.
    Calibrating to standard '15 with screw under black flap

    Figure 6: Calibrating to Standard ‘15’

  4. Calibrate to a Slope “15” readout. Cut off a small ½ inch piece of the test strip and cover both of the censor holes with it. Drop 2 drops from the Slope CS-15 bottle on the test strip. Watch the readout. If it does not read “15” do the following to adjust to “15”:
    1. Use your thumbnail/small screwdriver tool to gently lift the soft vertical black bar to the right of the readout area.
    2. There is a small screw under it. Use the screwdriver end of the small blue tongs to very gently adjust to a “15” readout (figure 5).
  5. Repeat step 1 to clean your meter sensor back down to “0”.
  6. Repeat step 2 to get a “20” readout. If the readout is between19 – 21, you are ready to do your potassium test. If the readout is not between 19 – 21, repeat step one to clean it back to “0” and repeat the slope 15 (step 4) again, followed by cleaning back down to “0”.

**Continue alternating between step 2, cleaning to “0” and step 4, cleaning to “0” – until the meter holds the 20 and 15 settings. You can do your potassium test now. (Directions follow). After you have completed this extensive calibration procedure, you will not need to do it again for about a month or unless something happens to disturb the calibration.

BETWEEN MONTHLY CALIBRATIONS

Prior to each test, clean your meter down to “0”. Then using a test strip, drop two drops of CS–20 on the strip. If the result equals 19 - 21 X 100, clean back down to “0” and do your saliva test. If outside the 19-21 X 100 range, use the adjustment dial on the top right of the meter to gently adjust the reading to “20” X 100 before following the procedure below for your saliva potassium test.

Testing Your Potassium:

(Be sure your meter is cleaned down to “0”.)

You should not have eaten or drunk anything for 20 minutes prior to testing. Wash hands.

Placing test strip on tongue with small blue tongs

Figure 7: Getting saliva sample on test strip

  1. Cut a ½ inch piece of the test strip.
  2. Fill mouth with saliva, swallow and place the test strip on the tongue, (figure 7)
  3. Using small blue tongs, lift the test strip off tongue and place it over both of the sensor holes.
  4. Notice whether the readout is (X – 1 or X – 10 or X – 100)?
  5. If the readout is less than 500 the Cardy K+ Meter needs to be calibrated using the 15 x 10 solution. Clean the meter sensor with DI water and use the same procedure as used to calibrate the machine earlier for “20” readout but use the “15” solution and calibrate to 15 X 10 (figure 8). Clean the sensor and retest the saliva sample.

    Calibrating the Cardy Meter with '15' solution using the wheel on the top right of meter

    Figure 8: Re-calibrate the Cardy Meter with the "15" solution if the saliva reading is below 500ppm


  6. Example: 85 beside 10 = 850 ppm (parts per million) 85 beside 100 = 8500 ppm
    To convert PPM (parts per million) to MMOL (millimoles), you need to multiply this result by.026.
    Example: 850 X .026 = 22.1
  7. Using the Conversion Chart, find 22.1 in the middle column. Look at the number in the right column beside it. This is the blood serum result (about 4.39) that correlates with the saliva potassium result.

NOTE: Sometimes, like in this example, your result will not fall exactly on a number in the saliva result column. This is because there is not room to list every possibility on the chart.

Note also that the detail of variation of the saliva result is much greater than the blood serum result. This probably indicates a better defined result.

Expect all of this to become much easier as you practice for a few months.

Further Instructions

  1. If the sensor is new or has been inactive for over a month, drip 3 to 4 drops of either one of the standardizing solutions onto the sensor pad using a sampling sheet to “warm-up” the sensor for 20 to 30 minutes. The meter can be off. This improves sensor response time and reduces the drift of the readings.
  2. A stable meter reading occurs when the value on the LCD display has not changed for a period of three (3) seconds.
  3. Wait 30 to 45 seconds after the solution has been placed on the sensor pad when calibrating or making a reading. A functional sensor should reach a “stable” reading during that time.
  4. When measuring a sample, make sure that the sample is covering the two black round sensors in the sensor pad. The ion concentration cannot be measured if the electrodes are not covered by the sample.
  5. Use clean tweezers to handle the sampling sheet.
  6. In order to obtain measurement values of high repeatability, maintain identical conditions as much as possible.
  7. Any kind of soft wiping tissue may be used to blot the sensor pad dry after rinsing. Sometimes there will appear to be some liquid on a spot of the small electrode. It is normal, simply rinse and blotdry.

By Lois Harris and Deborah Cavel-Greant