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Centrifuge
Method Evaluation Chapters
Introduction
Initial Questions
Linearity
Precision
Interference
Recovery
Method Comparison
Lower Limit of Detection
Carryover
Reference Ranges
Periodic Reevaluation
Second Instrument of Similar Make
Appendix A
Appendix B
Method Evaluation

Initial Questions

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The following information should be evaluated and found to be consistent with the laboratory's operational goals before a method or instrument is considered for further evaluation.



How will the test be used?
  • How often is the test being sent to a reference laboratory?
  • Will it become a standard of medical care?
  • Is this an individual, departmental, or general medical staff request?
  • Which physician groups will order the test?
  • How many tests will be ordered per week?
  • What is an acceptable turnaround time for inpatients and outpatients?
  • Does the test need to be available on a stat basis?
  • How would local availability of this test improve medical practice?
Physical Requirements
  • How much floor space is required?
  • What are the electrical requirements? Is a UPS required? Will it be supplied?
  • How much heat will be generated?
  • How are temperature fluctuations tolerated?
  • What range of relative humidity is tolerated?
  • What is the effect of static electricity?
  • Are there known hazards?
  • Is ancillary equipment required? (refrigerator, centrifuge, vortex, mixer, etc)
Reagents
  • What are the storage requirements at the projected test volume?
  • How much reagent preparation time is required?
  • How long are the reagents stable on the instrument?
  • How many tests can be stored on-board for each analyte?
  • How many analytes can be stored on-board at one time?
  • How much down time is required to replace regeants?
  • Is recalibration or control required after each reagent lot change?
  • How much lot to lot bias occurs for each analyte?
  • Is "on time" delivery of the same reagent lot available?
  • Does the instrument inform the operator of on-board inventory?
  • Are the reagents packaged in convenient size containers or volumes?
  • What is the reagent shelf life?
Disposal Requirements
  • How many consumables will be discarded (sample cups, cuvettes, microplates, pipettes, tips, tubing, lamps)?
  • Is a recycling program available?
  • Are any of the disposables considered biohazards?
Maintenance
  • How much time is required for daily, weekly, & monthly maintenance?
  • What is the start up time from stand-by?
  • What is the shut down time?
Sample Throughput Rate & Analysis Time
  • How many minutes elapse from introduction of the first sample to results.?
  • How much time elapses between subsequent samples & results?
  • What is the maximum number of samples performed per hour?
  • Will the system auto-dilute and automatically rerun dilutions?
  • Does stat interrupt capability exist? If so, what is the delay?
  • Is continuous random access testing available?
  • Is turnaround time significantly different than the current method?
  • How many different tests can be run on each sample in a single run?
Sample Handling
  • What is the sample size?
  • What is the dead space volume?
  • Is primary tube sampling available?
  • Is closed container sampling available?
  • Can tubes of different size be intermixed?
  • How many samples can be loaded at one time?
  • What specimen types can be run: Serum, plasma, urine, CSF?
  • Do any tests require special sampling (e.g. tubes, transportation)?
Calibration
  • What is the frequency and cost of calibration?
  • Is calibration performed manually or automatically?
  • Can other vendor's calibrators be used?
  • Can the slope and intercept be changed?
  • How many calibrations for an analyte can be stored for use?
  • Do calibrators include the full range of claimed linearity?
  • Does the vendor provide a 0 calibrator? If so, what is it?
  • Can aqueous standards be used?
Quality Control
  • How often must controls be run?
  • How many levels of control must be run?
  • Is on-line quality control review available?
  • Do protocols and actual examples exist for standardized quality control ranges across multiple like analyzers?
Test menu
  • What is the complete list?
  • What tests are planned for release in the next quarter?
  • Are user defined tests available?
  • Are there matrix issues for patient samples, controls, calibrators, or proficiency test samples?
  • Are standard methods, units, and reference ranges used?
  • What lower limit of detection is claimed for each test?
  • What are the linearity claims for each test?
  • How does the analyzer report values above the upper limit or under the lower limit?
Interference
  • Are any tests interfered with by hemoglobin, lipid, bilirubin?
  • Do any other commonly used clinical substances (drugs) cause interference?
  • Is carryover a problem for any test?
Performance History
  • How reliably has the instrument performed in other users' laboratories?
  • How has the instrument performed in proficiency surveys?
  • Is proficiency testing available from the usual sources?
Training
  • Is training offered on-site and/or at the manufacturer's facility?
  • How many training slots are offered per instrument?
  • Is field support available for repeated on-site training?
Service
  • Are self-diagnostics available? Via telecommunication?
  • What is the repair record of analyzers in the field?
  • What is the average down time experienced by other users?
  • Is field service local? How many service technicians cover the territory?
  • How much time is allowed before service responds by phone?
  • How much time is allowed before service arrives on-site?
  • What type of back-up is available in the event of significant down time?
Staff requirements
  • Can operators walk away from the instrument?
  • How many like instruments can one operator run if they are in close proximity?
Computer capability
  • Is the interface bidirectional?
  • Has the instrument been interfaced to our LIS at other installations?
  • Can the analyzer be interfaced during evaluation?
  • Is the interface provided without charge?
  • Is bar code capability available? What are the specifics of placement?
Cost
  • What is the direct cost per reportable (billable) result?
  • What purchase options are available (lease, purchase, reagent rental)?
  • What does the service contract cost? Is it necessary?
  • What is the warranty?