1. Scales and Balances Stan Zurek (2006), Electronic weighing scale [photograph]. Retrieved from https://commons.wikimedia.org/wiki/File:Waga_elektroniczna.jpg

2. Quiz Clinical Use History Specifications Principles of Operation Block Diagram Commercial Examples Preventive Maintenance Common Problems Test Procedures Summary

3. Analyze body fluids and tissues for specific substances of interest Report the results to clinicians for diagnosis and treatment Clinical Laboratory Bobjgalindo (2004), Holy Rosary Hospital Laboratory [photograph]. Retreived from https://commons.wikimedia.org/wiki/File:Hospital_Laboratory.JPG

4. Functions: 1.Chemistry: Blood, urine, cerebrospinal fluid, etc. determine how much of a substance is present 2. Hematology: Number and characteristics of elements in blood (RBC, WBC, platelets, etc.), blood clotting tests 3. Microbiology: test blood and tissue cultures for presence of microorganisms 4. Blood bank: Determination of blood type 5.Solution/reagent component measurement Clinical Laboratory

5. Balances in the Clinical Labratory –Main areas Sample rack Analytic instrument Centrifuge Dilute, dispense equipment Scale Lab solution component measuring Clinical Laboratory

6. Oldest means of measurement fifth century B.C. Mesopotamia and Egypt Balances/Scale History Toby Hudson (2011), Brass weight scales with flat trays [image]. Retrieved from https://commons.wikimedia.org/wiki/File:Brass_scales_with_flat_trays_balanced.png

7. Clinical Use Clinical laboratories –Analytical balance -Measure the weight or mass of a substance (+/- 0.0001g accuracy/repeatability or better) –Table top balance (scale) General clinics – scale diagnostic Algont (2006), Digital Scale [photograph]. Retrieved from https://commons.wikimedia.org/wiki/File:Digi- keukenweegschaal1284.JPG

8. Principles of Operation Categories: –Mechanical (Springs/lever arms) –Electrical (strain gauge) –Electromagnetic (current needed to levitate the pan and mass)

9. Principles of Operation Electromagnetic Balance: (2015), Electromagnetic Type [diagram]. Retrieved from: http://www.shimadzu.com/an/balance/support/hiroba/bean/bean04.html

10. Analytical scale basic parts: Principles of Operation Algont (2006), Digital Scale [photograph]. Retrieved from https://commons.wikimedia.org/wiki/File:Digi- keukenweegschaal1284.JPG Glass case Door access pan Leveling screw

11. Controls ON/OFF Tare Zero (optional) Others (Calibration, print, menu, function, etc…) Stan Zurek (2006), Electronic weighing scale [photograph]. Retrieved from https://commons.wikimedia.org/wiki/File:Waga_elektroniczna.jpg

12. Mechanical Balances WHO, Maintenance and Repair of Laboratory Equipment (1996). Retrieved from library.ewh.org

13. Circuit Cast aluminum chassis Main mother board LCD display Force restoration motor assembly Power supply p.c. board.

14. Commercial Examples Stan Zurek (2006), Electronic weighing scale [photograph]. Retrieved from https://commons.wikimedia.org/wiki/File:Waga_elektroniczna.jpg

15. Electromagnetic balances -User error: lack of calibration, overweight -Environment factors: temperature, static electricity, vibration, out of level (tilted), and wind Common Problems

16. Mechanical balances/scales -User error: lack of calibration, overweight -Maintenance: rusted parts, lack of oil (Lubrication) -Environment factors: temperature, out of level (tilted) Common Problems

17. Test weight(s) - never touch a standard weight with bare hands! Check for Accuracy and repeatability. (2point test) - Test weights tolerance must exceed scale/balance accuracy by a factor of 4 as a minimum - normally at 30-50% and 70-100% of max capacity - Platform scales/balances require testing at each corner of platform - for Calibration see manufacturer's procedures Clean unit and weighing surface Check operation of level and adjusters Test Procedures for Balances and Scales

18. Questions ?