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Standard operating procedure
Calibration No: 017D
Calibration of equipment plays an essential part in ensuring
that the equipment is functioning correctly. It is essential
that all equipment is calibrated at the specified time, in order
that potential calibration drifts can be addressed. Equipment
that has not been calibrated may give rise to inaccurate results,
leading to inaccurate research findings.
Research nurses trained in the method are responsible for calibrating
all study equipment.
ultrasonic height measure
HEM 705CP blood pressure machine
details should be dated and recorded in the designated calibration
record book. Any major calibration drifts or any problems with
the equipment should be discussed with either Janine Pembroke
or Dr Mark Caulfield. All equipment used for the phenotypic
measurements of subjects should be calibrated using the following
or buy 4 weights of 20kgs each (plastic boxes filled with
dry sand can be made up to 20kgs). Use these weights for all
the calibration measurements.
the standing platform on a flat uncarpeted floor. Switch the
scales on as before.
the 4 weights, test 3 separate weight measurements. Document
any calibration drifts, so subject results can be amended
the calibration format in the manufacturing manual, Press
SLOW and hold down. Then press UNITS and hold down (while
still holding slow).
ZERO 6 times (while still holding SLOW and UNITS). The scales
should now enter calibration mode. When CAL appears in the
viewfinder, release SLOW, UNITS and ZERO.
NEXT to set ZERO.
selected the calibration weight, load this weight onto the
scale, wait a second or two and then press NEXT. After the
weight has been recorded, DONE will appear in the viewfinder,
alternating with the weight. Ensure the scales have recorded
the correct weight. Should there be any drift, calibrate the
scale to the correct weight by pressing the HOLD key as required.
When the correct weight is displayed in the viewfinder, press
3 separate weight measurements on each scale. Record all the
results in the calibration record book. Each scale should
be calibrated every month.
height measure has no inbuilt calibration mode. However, it
should be calibrated every month so calibration drifts can
the weights, have 3 specially made height measuring tools
for calibration. For example 3 rods: 1 x 2 foot, 1 x 3 foot
and 1 x 5 foot. The same rods should be used for all calibration.
month check the height measure with all 3 calibration rods.
Subjects heights should be corrected according to any calibration
drifts (if any). All calibration drifts should be recorded
in the calibration record book and phenotypic measurements
should be correctly recorded. Any major calibration drifts
should be discussed with the study co-ordinators.
to the manufacturer the height measure battery should last
for 10 years. Any major problems with the machine should be
discussed with the study co-ordinators.
tape has an inbuilt tension mechanism which needs to be calibrated
on a monthly basis.
- To calibrate
the tape a wooden metre rule is needed. Using the ruler, take
3 separate measurements. The reading on the ruler should be
the same as the reading on the tape. If the three measurements
are not the same, replace the tape. New tapes can be acquired
from the Nurse Co-ordinator.
to the manufacturer, the tape should be suitable for approximately
all calibration results in the calibration record book.
three solid blocks made of three separate thickneses, for
example 10, 20 and 30mm. Use these blocks for all the calibration
tests using the skinfold calipers.
the calipers to the blocks and ensure the correct reading
is displayed on the caliper dial.
in the caliper reading can be achieved by turning the knob
on the right hand side of the dial. Adjust the dial, so the
correct reading appears in the dial.
- Use all
three blocks and ensure the readings are correctly displayed.
the caliper reading always rests on zero, when not in use.
all calibration readings in the calibration record book on
a monthly basis.
HEM 705CP blood pressure machine
blood pressure machines should be calibrated every 3 months.
Two people are required to calibrate one machine.
a three way valve on the blood pressure machine at the junction
where the blood pressure cuff is attached. Attach the cuff
on one side of the three way valve. On the other connection
attach a standard spygmanometer. Attach the cuff onto the
left arm of one of the observers.
- The observer
with the cuff on the arm should press the start button, on
the Omron machine. The other observer should listen to the
blood pressure by using the stethoscope and observing the
pressures in the spygmanometer.
3 separate readings and record the findings in the calibration
- Any calibration
drifts should be reported to the Nurse Co-ordinator, who will
replace the Omron machine.
ECG machine and Spacelabs ABP machines
two machines do not need to be calibrated at each centre.
The Nurse Co-ordinator will inform the relevant centre if
their machines need to be serviced and will arrange how best
this can be achieved with that centre. Any problems with these
two machines should be directed at the Nurse or Medical Co-ordinators.
5. Additional Information
that all equipment is calibrated at the correct time and the
relevant details are recorded in the calibration record book.