these are some errors mostly related to clinical laboratory.

3. ERROR
• AN ERROR IS THE DIFFERENCE BETWEEN THE TRUE RESULT AND THE MEASURED
RESULT.
• IF THE ERROR IN AN ANALYSIS IS LARGE, SERIOUS CONSEQUENCES MAY RESULT.
• A PATIENT MAY UNDERGO SERIOUS MEDICAL TREATMENT BASED ON AN
INCORRECT LABORATORY RESULTS.

4. IN OTHER WORDS
• LABORATORY ERRORS ARE DESCRIBED AS DEFECTS OCCURRING AT ANY PART OF
THE LABORATORY SYSTEMS, FROM ORDERING TESTS TO REPORTING RESULTS
AND APPROPRIATE INTERPRETATION AND REACTION TO THESE ERRORS.
• ERRORS IN LABORATORY MAY OCCUR AS A RESULT OF THE FAILURE ON THE
LABORATORY SYSTEMS AND PROCESSES.

5. SOME COMMON LABORATORY ERRORS
• PATIENT ID ERROR
• LOST SAMPLE
• SAMPLE DELAYED IN TRANSIT
• CONTAMINATED SAMPLES
• WRONG TEST PERFORMED
• TEST PERFORMED INCONSISTENT WITH
THE WRITTEN PROCEDURE
• PROFICIENCY TESTING ERROR
• NO ACTION ON OUT OF RANGE
CONTROLS
• FALSE NEGATIVE/POSITIVE RESULT
• LATE REPORTS
• MISSING REPORTS
• COMPLAINTS
• LABORATORY ACCIDENT
• “NEAR MISS”

6. equipment
not properly
maintained
QC, EQA
not
performed
test kits
not stored
properly
transcription
errors
checks
not done
training
not done
or
not completed
written
procedures
not followed
no written
procedures
individual
responsibilities
unclear
Common
causes of
error

7. THE PATIENT Test Sample Collection
Sample Transport
Laboratory Analysis (Examination Phase)
Report Creation
Report Transport
Pre-examination Phase
Result Interpretation Post-examination Phase
selection

8. PHASES OF ERRORS IN TESTING PROCESS
TOTAL TESTING PROCESS IS TYPICALLY DIVIDED INTO THREE MAIN PHASES;
1. PRE-ANALYTICAL
2. ANALYTICAL
3. POST-ANALYTICAL
• STUDIES HAVE DEMONSTRATED THAT A LARGE PERCENTAGE OF LABORATORY
ERRORS OCCUR IN PRE AND POST-ANALYTICAL PHASES, WITH FEWER ERRORS
OCCURRING DURING THE ANALYTICAL PHASE.

9. PRE-ANALYTICAL ERRORS
EXAMPLES INCLUDED:
• WRONG SAMPLE COLLECTED
• SAMPLE MISLABELED OR UNLABELED
• SAMPLE STORED INAPPROPRIATELY BEFORE TESTING
• SAMPLE TRANSPORTED INAPPROPRIATELY
• REAGENTS OR TEST KITS DAMAGED BY IMPROPER STORAGE

10. ANALYTICAL ERRORS
EXAMPLES INCLUDED:
• ESTABLISHED ALGORITHM NOT FOLLOWED
• INCORRECT TIMING OF TEST
• RESULTS REPORTED WHEN CONTROL RESULTS OUT OF RANGE
• IMPROPER DILUTION AND PIPETTING OF SAMPLE OR REAGENTS
• REAGENTS STORED INAPPROPRIATELY OR USED AFTER EXPIRATION
DATE

11. POST ANALYTICAL ERROR
EXAMPLES INCLUDED:
• TRANSCRIPTION ERROR IN REPORTING
• REPORT ILLEGIBLE
• REPORT SENT TO THE WRONG LOCATION
• REPORT NOT SENT

12. RISK OF LABORATORY ERRORS
Inadequate or
inappropriate
patient care
Inappropriate
public health
action
Wasteful of
resources
Death
Undetected
communicable
disease outbreaks
ERROR

13. ANOTHER CLASSIFICATION
• ERRORS CAN ALSO BE CLASSIFIED INTO FOLLOWING CATEGORIES:
1. DETERMINATE (SYSTEMIC) ERRORS: THE ERROR IS REPRODUCIBLE AND CAN BE
DISCOVERED AND CORRECTED.
2. INDETERMINATE (RANDOM) ERRORS: CAUSED BY UNCONTROLLABLE
VARIABLES, WHICH CAN NOT BE DEFINED/ELIMINATED.

14. PRECISION AND ACCURACY
• TWO TERMS ARE COMMONLY ASSOCIATED WITH ANY DISCUSSION OF ERROR:
"PRECISION" AND "ACCURACY".
• PRECISION REFERS TO THE REPRODUCIBILITY OF A MEASUREMENT.
• ACCURACY IS A MEASURE OF THE CLOSENESS TO TRUE VALUE.
• THE CONCEPTS OF PRECISION AND ACCURACY ARE DEMONSTRATED BY THE
SERIES OF TARGETS BELOW.
• IF THE CENTER OF THE TARGET IS THE "TRUE VALUE", THEN A IS NEITHER
PRECISE NOR ACCURATE. TARGET B IS PRECISE (REPRODUCIBLE) BUT NOT
ACCURATE. THE AVERAGE OF TARGET C'S MARKS GIVE AN ACCURATE RESULT
BUT PRECISION IS POOR. TARGET D DEMONSTRATES BOTH PRECISION AND
ACCURACY - WHICH IS THE GOAL IN LAB.

17. DETERMINATE ERROR
• DETERMINATE ERRORS ARE CAUSED BY FAULTS IN THE ANALYTICAL PROCEDURE
OR THE INSTRUMENTS USED IN THE ANALYSIS.
• THE NAME DETERMINATE ERROR IMPLIES THAT THE CAUSE OF THIS TYPE OF
ERROR MAY BE FOUND OUT AND THEN EITHER AVOIDED OR CORRECTED.
• DETERMINATE ERRORS ARE SYSTEMATIC ERRORS; THAT IS, THEY ARE NOT
RANDOM.
• A PARTICULAR DETERMINATE ERROR MAY CAUSE THE ANALYTICAL RESULTS
PRODUCED BY THE METHOD TO BE ALWAYS TOO HIGH OR TOO LOW.
SOMETIMES THE ERROR IS CONSTANT.
• ALL RESULTS ARE TOO HIGH (OR TOO LOW) BY THE SAME AMOUNT.

18. • DETERMINATE ERRORS CAN BE ADDITIVE OR THEY CAN BE MULTIPLICATIVE. IT
DEPENDS ON THE ERROR AND HOW IT ENTERS INTO THE CALCULATION OF THE
FINAL RESULT.
• THIS DETERMINATE ERROR COULD BE THE RESULT OF AN INCORRECTLY
CALIBRATED BALANCE.
• IF THE BALANCE IS SET SO THAT THE ZERO POINT IS ACTUALLY 0.5 MG TOO
HIGH, ALL MASSES DETERMINED WITH THIS BALANCE WILL BE 0.5 MG TOO HIGH.
• THE ERROR IS REPORTED AS THE ABSOLUTE ERROR, THE ABSOLUTE VALUE OF
THE DIFFERENCE BETWEEN THE TRUE AND MEASURED VALUES.

19. • DETERMINATE ERRORS ARISE FROM SOME FAULTY STEP IN THE ANALYTICAL
PROCESS.
• THE FAULTY STEP IS REPEATED EVERY TIME THE DETERMINATION IS PERFORMED.
WHETHER A SAMPLE IS ANALYZED 5 TIMES OR 50 TIMES, THE RESULTS MAY ALL
AGREE WITH EACH OTHER (GOOD PRECISION) BUT DIFFER WIDELY FROM THE
TRUE ANSWER (POOR ACCURACY).

20. INSTRUMENT ERRORS
• FAILURE TO CALIBRATE, DEGRADATION OF PARTS IN THE INSTRUMENT, POWER
FLUCTUATIONS, VARIATION IN TEMPERATURE, ETC.
• IT CAN BE CORRECTED BY CALIBRATION OR PROPER INSTRUMENTATION
MAINTENANCE.
METHOD ERRORS
• ERRORS DUE TO NO IDEAL PHYSICAL OR CHEMICAL BEHAVIOR-COMPLETENESS AND
SPEED OF REACTION, INTERFERING SIDE REACTIONS, SAMPLING PROBLEMS
• IT CAN BE CORRECTED WITH PROPER METHOD DEVELOPMENT.
PERSONAL ERRORS
• OCCUR WHERE MEASUREMENTS REQUIRE JUDGMENT, RESULT FROM PREJUDICE,
COLOR ACUITY PROBLEMS.
• IT CAN BE MINIMIZED OR ELIMINATED WITH PROPER TRAINING AND EXPERIENCE.

21. • ANALYST ERROR : THE PERSON PERFORMING THE ANALYSIS CAUSES THESE
ERRORS.
• THEY MAY BE THE RESULT OF INEXPERIENCE, INSUFFICIENT TRAINING, OR BEING
“IN A HURRY”.
• AN ANALYST MAY USE THE INSTRUMENT INCORRECTLY,
• PERHAPS BY PLACING THE SAMPLE IN THE INSTRUMENT INCORRECTLY EACH TIME.
• SETTING THE INSTRUMENT TO THE WRONG CONDITIONS FOR ANALYSIS.
• IMPROPER USE OF PIPETTES, SUCH AS “BLOWING OUT” THE LIQUID FROM A
VOLUMETRIC PIPETTE.

22. • SOME OTHER ANALYST-RELATED ERRORS ARE
• CARELESSNESS
• TRANSCRIPTION ERRORS, THAT IS, COPYING THE WRONG INFORMATION INTO A LAB
NOTEBOOK OR ONTO A LABEL
• CALCULATION ERRORS.
• PROPER TRAINING, EXPERIENCE, AND ATTENTION TO DETAIL ON THE PART OF
THE ANALYST CAN CORRECT THESE TYPES OF ERRORS.

23. INSTRUMENTATION ERRORS
• NUMEROUS ERRORS INVOLVING INSTRUMENTATION ARE POSSIBLE, INCLUDING
• USE OF IMPROPER OR EXPIRED STANDARD SOLUTIONS TO CALIBRATE INSTRUMENTS
• INCORRECT INSTRUMENT ALIGNMENT
• INCORRECT WAVELENGTH SETTINGS
• INCORRECT READING OF VALUES, AND
• INCORRECT SETTINGS OF THE READOUT (I.E., ZERO SIGNAL SHOULD READ ZERO).
ANY VARIATION IN PROPER INSTRUMENT SETTINGS CAN LEAD TO ERRORS.
• THESE PROBLEMS CAN BE ELIMINATED BY A SYSTEMATIC PROCEDURE TO CHECK
THE INSTRUMENT SETTINGS AND OPERATION BEFORE USE. SUCH PROCEDURES
ARE CALLED STANDARD OPERATING PROCEDURES (SOPS) IN MANY LABS.
• THERE SHOULD BE A WRITTEN SOP FOR EACH INSTRUMENT AND EACH
ANALYTICAL METHOD USED IN THE LABORATORY.

24. DETECTION OF SYSTEMATIC ERRORS
1. ANALYSIS OF STANDARD SAMPLES
2. INDEPENDENT ANALYSIS: ANALYSIS USING A "REFERENCE METHOD" OR
"REFERENCE LAB“
3. BLANK DETERMINATIONS
4. VARIATION IN SAMPLE SIZE: DETECTS CONSTANT ERROR ONLY

25. RANDOM (INDETERMINATE) ERROR
• IT OCCURS ACCIDENTALLY OR RANDOMLY SO CALLED AS INDETERMINATE OR
ACCIDENTAL OR RANDOM ERROR. ANALYST HAS NO CONTROL IN THIS ERROR.
• NO IDENTIFIABLE CAUSE
• ALWAYS PRESENT
• CANNOT BE ELIMINATED
• THE ULTIMATE LIMITATION ON THE DETERMINATION OF A QUANTITY.
• EX. READING A SCALE ON AN INSTRUMENT CAUSED BY THE FINITE THICKNESS
OF THE LINES ON THE SCALE; ELECTRICAL NOISE

26. INDETERMINATE ERRORS
• INDETERMINATE ERRORS ARE NOT CONSTANT OR BIASED.
• THEY ARE RANDOM IN NATURE
• THEY ARE THE CAUSE OF SLIGHT VARIATIONS IN RESULTS OF REPLICATE
SAMPLES MADE BY THE SAME ANALYST UNDER THE SAME CONDITIONS.
• SOURCES OF RANDOM ERROR INCLUDE THE LIMITATIONS OF READING
BALANCES, SCALES SUCH AS RULERS OR DIALS, AND ELECTRICAL “NOISE” IN
INSTRUMENTS.
• FOR EXAMPLE, A BALANCE THAT IS CAPABLE OF MEASURING ONLY TO 0.001 G
CANNOT DISTINGUISH BETWEEN TWO SAMPLES WITH MASSES OF 1.0151 AND
1.0149 G.

27. • THESE RANDOM ERRORS CAUSE VARIATION IN RESULTS, SOME OF WHICH MAY
BE TOO HIGH AND SOME TOO LOW.
• INDETERMINATE ERRORS ARISE FROM SOURCES THAT CANNOT BE
• CORRECTED
• AVOIDED
• IDENTIFIED, IN SOME CASES.
• HOWEVER, BECAUSE INDETERMINATE ERROR IS RANDOM, THE ERRORS WILL
FOLLOW A RANDOM DISTRIBUTION.
• THIS DISTRIBUTION CAN BE UNDERSTOOD USING THE LAWS OF PROBABILITY
AND BASIC STATISTICS. THE EXTENT OF INDETERMINATE ERROR CAN BE
CALCULATED MATHEMATICALLY.

28. IN OTHER WORDS
• ACCURATE MEASUREMENTS HAVE LITTLE DETERMINATE ERROR.
• DETERMINATE ERROR DEGRADES ACCURACY BUT HAS NO EFFECT ON
PRECISION.
• PRECISE MEASUREMENTS HAVE LITTLE INDETERMINATE ERROR.
• INDETERMINATE ERROR DEGRADES PRECISION BUT IT DOES NOT INFLUENCE
ACCURACY.

29. THANK YOU
THANK
YOU