Basics of calibrations & performance verificationof non analytical instruments

Dr K Krishnan

5.3.1.4 Equipment calibration and metrological traceability

The laboratory shall have a documented procedure for the calibration of equipment that directly or indirectly affects examination results. This procedure includes:

a) taking into account conditions of use and the manufacturer’s instructions;

b) recording the metrological traceability of the calibration standard and the traceable calibration of the item of equipment;

c) verifying the required measurement accuracy and the functioning of the measuring system at defined intervals;

d) recording the calibration status and date of recalibration;

e) ensuring that, where calibration gives rise to a set of correction factors, the previous calibration factors are correctly updated;

f) safeguards to prevent adjustments or tampering that might invalidate examination results.

22/02/2014 FQI ISO 15189 IA & QMS certificate course

• Metrological traceability shall be to a reference material or reference procedure of the higher metrological order available.

• NOTE Documentation of calibration traceability to a higher order reference material or reference procedure may be provided by an examination system manufacturer. Such documentation is acceptable as long as the manufacturer’s examination system and calibration procedures are used without modification.

• Where this is not possible or relevant, other means for providing confidence in the results shall be applied, including but not limited to the following:

— use of certified reference materials;

— examination or calibration by another procedure;

— mutual consent standards or methods which are clearly established, specified, characterized and mutually agreed

upon by all parties concerned.

22/02/2014 FQI ISO 15189 IA & QMS certificate course

Equipments that indirectly affect results

• Parts of Analyzer which may / may not be integrated but contribute indirectly to results:

• Pre Analytical Phase– Centrifuge – Water bath– Autoclave– Pipette– Storage chambers, Environment– HIT indices measuring component

• Automation of non – analyzer component– Engen™

Calibration requirements - general

• Appropriate to the equipment

• SOP of calibration defined

• Certification a must

• Signed off by the qualified engineer / agency

• Traceability certificate copy required for the instrument used for any calibration

Calibration certificate contents

The calibration certificates issued by external agency must be checked for following details:

• Name of Certificate issuing agency

• Date of issuance

• Description of the equipment under calibration

• Standards / Calibrators used for the calibration of the reference

• Date of Calibration

• Calibration results

• Acceptance criteria

• Next calibration due date

• Traceability to national/international standards

• Copies of calibration certificate of the standard / calibrator with traceability to national / international standards (if applicable).

Centrifuge• Indicators on the instruments

– Speed– Temperature ?

• Calibration of speed– Tachometer ( Traceability to reference standard and calibrated)

• Indicator display should match the actual reading with tolerance limits prescribed by the manufacturer

• Frequency : every PM event / as required • Centrifuge should be fully loaded• Speed requirement specific for the tests done• Speed required for tests defined:

– as per tests – As per type of tubes used

– Temperature:• Calibrated thermometer equipment used for calibrating temp

display • Tolerance limit defined

Source: tech talk BD Diagnostics Vol 6, 2008

Water baths calibration

• Correction Factor = the difference in the NIST traceable thermometer and the Observed Temperature measured by the NIST traceable thermometer. This is calculated and reported during the annual certification of the thermometers

• The True Temperature measured by the laboratory thermometer = the Observed Temperature plus the correction factor for that thermometer

• Equipment used: NIST traceable thermometer

• Frequency: Annual

Source: EPA/OPP MICROBIOLOGY LABORATORY ESC, Ft. Meade, MD Standard Operating Procedure for Calibration of Thermometers

Autoclave calibrationFrequency of controls:

• With chemical Indicator : Every load

• With Biological indicator: Every month

Calibration Procedure:

• Temperature indicator, Pressure gauge and probe should be calibrated quarterly / on extensive maintenance – Temperature gauge: Benzoic acid Grade AR: melts at 121°C:– Pressure: A standard calibrated gauge attached to a T

connection and pressure compared – Limits: +5 % psi, – Temperature indicator calibrated using silicon oil bath and std

thermometer at 100° C and 125° C (Limit: + 1°C)

Source: S S Jadiya, School of Pharma Sciences, RGTU UIT, Bhopal

Calibrating a pipette for actual volume

VOLUMEPipette :Water Temperature:Density From Table: 0.9982Technician:Date :Balance :

Measure Actual Volume Weight Volume calc. Limits

No (µl) (g) (µl) (%)

1 1000 0.988 989.8 -2 0.0 -3 0.0 -4 0.0 -5 0.0 -

°C Density

18 0.9986

19 0.9984

20 0.9982

21 0.998

22 0.9978

23 0.9975

24 0.9973

25 0.997

26 0.9968

27 0.9965

28 0.9962

Storage chambers:calibration and validation

Specify range of temperature for storage

The objectives:

• To calibrate temperature display with calibrated equipment (as for water baths with NIST thermometers)

• To identify the hot and cold zones in storage chambers,

• To challenge the storage temperature by keeping the chambers open for fixed time

• To find the maximum time allowable for power shut downs

Calibrating storage chambers

Three types of validation to be conducted with the sensors located at different places:

• The Static Mapping

• The Dynamic mapping

• The Power cut-off and recovery mapping

Equipment ID Accuracy Calibration

validity

Data Logger

(36 CH)

Make: Chino

+ 0.5 °C 31st Oct

2014

RTD Pt-100

Sensor 4

wire

+ 0.5 °C 24th Nov

2014

Characterization of equipment used to calibrate storage

Measuring HIT indices

• Manual inspection– Color index grade I to IV– Visual grading as per a given chart– Range of hemolysis, turbidity and icterus to be determined for

each grading using dedicated reagents

• Automated Systems– Integrated with Analyzer

• Usually done with dedicated reagents for measuring hemolysis, turbidity and Bilirubin

• Throughput may be affected– VITROS Microsensor technology is unique method

• No reagents used• Hence Throughput not affected

VITROS MicroSensor™

MicroSensor™ - How it Works

Reflectometer

Spectrophotometer

Grating & Photodiode Array

Electronics A/D, DSP,

S/W

Collect Light from Reflectometer

Lamp

Shine Light Through Patient

Sample

Measure Spectrum of Transmitted

Light

Master Computer Software

Communicate Absorbance

Spectrum

Convert Spectra a to Semi-

Quantitative Indice Values

Absorbance Spectrum

0

0.5

1

1.5

2

400 450 500 550 600 650 700 750 800

Wavelength

Abs

orba

nce

Bilirubin

Turbidity

Hemoglobin

Absorbance Spectrum is acquired for each sample.Spectrum is used to make predictions for the three indices.

Controls to be run weekly to cross check No calibration required as no reagent used

Cost of not calibrating non- analytical equipments

Automation of pre analyticals

enGen™•Sample processing – decapping, centrifugation

•Sample transport with intelligent routing

•Rules-based reflex & repeat testing

•Result verification

The only calibration required is for thecentrifuge