Good laboratory practices with waived test systems

1
Good laboratory practices with waived test
systems

• January 2002
• Washington State Department of Health
• Office of Laboratory Quality Assurance
• [phone] www.doh.wa.gov/lqa.htm

2
What is a waived test?

• Under CLIA, tests are categorized by complexity
• Waived, PPMP, Moderate, High
• Waived tests are
• Simple lab examinations or procedures
• Cleared by FDA for home use
• Negligible likelihood of erroneous results
• No reasonable risk of harm if performed
  incorrectly

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What does waived mean?

• Waived from most requirements established for
  tests of higher complexity
• Site inspections are not routinely performed
• Proficiency testing is not required
• Personnel qualifications are not established

4
What do the Washington State regulations say for
waived testing?

• Obtain a Medical Test Site license
• Tell us which waived tests you perform
• Follow manufacturers instructions for
  performance of the test

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Waived tests are simple, but

• Any test can produce erroneous results if not
  performed properly
• Any test worth running should be associated with
  good laboratory practices
• What are good laboratory practices?
• What are good risk management practices?

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Have a current product insert

• Make sure it states CLIA waived
• For some tests (defined in regulations) all are
  waived (i.e., fecal occult blood)
• For some tests only certain specific test
  systems are waived (i.e., Strep antigen)
• For some test kits test may be waived or
  moderate complexity, depending on specimen used
  (i.e., mononucleosis whole blood
  is waived, serum or plasma is moderate complexity

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Focus on these sections

• Intended use
• Product storage
• Precautions/Warnings
• Patient preparation
• Specimen collection
• Test procedure

• Procedural notes
• Quality control
• Results/Interpretation
• Limitations
• Expected results

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• In the following slides, we give examples (in
  quotations) from actual product inserts to show
  the kinds of information you will find in the
  various sections of the product insert

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Intended use

• Describes what is actually being measured
• measures percent concentration of HgbA1C in
  blood
• Qualitative versus quantitative
• qualitative detection of Group A Strep antigen
  directly from throat swab
• Type of specimen
• not recommended for use with gastric specimens

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Product storage

• Kits, reagents, test devices
• store refrigerated at 2 8 degrees C
• keep 3 months at room temperature
• cassettes must be stored in sealed foil pouches
• store out of sunlight
• strips must be kept in bottle with cap tightly
  closed

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Precautions / Warnings

• Proper handling of kits, reagents, test devices
• do not use past expiration
• do not mix components of different lots or kits
• should not be interpreted by individuals with
  blue color deficiency (color blindness)
• do not interchange caps on reagents

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Patient preparation

• Examples
• CLO test
• discontinue use of antibiotics and bismuth
  preparations 3 weeks before biopsy
• Occult blood
• for 7 days avoid non-steroidal
  anti-inflammatory drugs, for 3 days avoid
  vitamin C in excess of 250 mg a day, avoid red
  meats

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Specimen collection, handling

• Acceptable types of specimens
• finger stick or venipuncture
• can be stored at room temperature for 4 hours
  and up to 72 hours if refrigerated
• do not use swabs that have cotton tips or wooden
  shafts
• Acceptable anticoagulants
• acceptable anticoagulants are EDTA, heparin,
  citrate, fluoride

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Test procedure/Directions/Instructions

• Follow exactly
• Dont modify
• Adhere to timing

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Procedural notes

• do not open foil pouch until ready to test
  avoid cross contamination read results within
  20 minutes
• directions must be followed exactly, accurate
  timing is essential
• allow specimen and test devices to warm to room
  temperature before use

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Quality control

• The types of controls to be tested vary with the
  specific test system used
• External, Internal, Electronic
• Test controls according to the manufacturers
  instructions
• Read the entire Quality Control section carefully
• Assure that you get the expected results for the
  controls tested

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Quality control

• External controls
• Reference solutions or materials (i.e., swabs)
• Added to test device like the patient sample
• May be included with the test kit or you may need
  to purchase separately
• Compare your control results to the expected
  ranges or values printed on the control vials or
  in the control product insert

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Quality control

• Internal (built-in, procedural) controls
• Built into test reagent devices to ensure that
  reagents are active, reagents samples are added
  correctly, test performs according to
  specifications
• Common with qualitative tests
• (Strep antigen, pregnancy, H. pylori,
  mononucleosis)
• Procedural controls typically include the
  appearance of a colored dot, line or bar in a
  control region and/or an expected appearance of
  the device background

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Quality control

• Electronic controls
• Inert, reusable devices
• (test strips, cartridges, cassettes)
• Used to check instrument performance
  specifications
• Available for use with some quantitative test
  systems
• (hemoglobin, cholesterol, A1C, prothrombin time)
• Compare the control results with the expected
  values

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Results / Interpretation

• Positive
• Negative
• Invalid
• Reportable range of method
• patient values are linear from 2.5 to 14.0
• linear up to 23.5 g/dl

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Limitations of procedure

• Causes of false positives, false negatives
• patients must have a total hemoglobin between 7
  and 24 g/dl
• measuring range is 100 to 500

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Expected results, values

• the following values are considered normal
• normal range is 4.3 - 5.7
• 95 of prothrombin time values range from 10.6
  to 13.4 seconds
• for the purposes of calculating the INR, normal
  is defined as 12.0 seconds
• will detect 20 mIU/ml of HCG

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Good laboratory practices

• Test controls - Follow manufacturer instructions
• positive and negative controls should be tested
  with each new lot or shipment of test materials
• Daily Requirements Two levels of electronic
  quality control or two levels of liquid controls
  must be tested
• a positive and negative control must be tested
  when opening a new test kit and with each change
  in operator within the test kit
• check the calibration daily by using the control
  cuvette

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Good laboratory practices

• At minimum, test external controls with each new
  lot of kits, reagents, testing devices
• To detect problems during shipment
• Observe internal (built-in, procedural) controls
  with each patient test
• To assure proper test performance, reagent
  integrity
• Test electronic controls periodically
• According to manufacturers instructions
  frequency

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Good laboratory practices

• Correlate test results with patient presentation,
  history, diagnosis
• Participate in a proficiency testing (PT) program
• Many PT companies offer 2 sample programs
• Split sample program
• Compare your results with reference laboratory

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Training

• Have new employees read the entire product insert
• Not just the Quick Reference Card
• Keep a record of training
• Have each employee demonstrate competency
• Initially
• Periodically

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Keep a simple log of results

• By keeping results of the following in
  chronological order, you can detect potential
  problems
• New lots of reagents, kits, testing devices
• Quality control results
• Patient test results

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Report test system problems

• To manufacturer
• To Food Drug Administrations MedWatch
• Call 1-800-FDA-1088

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Questions?

• Call the Office of Lab Quality Assurance
• [phone]
• Go to our website
• www.doh.wa.gov/lqa.htm