case presentation (lab analytical quality assurance problem )
TRANSCRIPT
Rania Mohamed [email protected]
Lecturer of clinical chemistry, MRI-Alexandria University ,CPHQ,LSSGBHealth governance –MRI-Alex university unit coordinator
IHI Egypt & NAHQ member
Case presentation
How can we achieve good laboratory practice?
1. A 64 year-old female went to the laboratory to perform the investigations requested from a referring doctor.
2. She went in to the registration unit
3. The receptionist asked the patient to fill the registration form , the patient was illiterate so the receptionist tried to help the patient and she asked for the following data:
How can we achieve good laboratory practice?
History taking
(1) Full name of the patient
(2) Age
(3) Telephone and Address of the patient
(4) Referring doctor name and address (contact)
(5) History of chronic illness
(6) History of surgeries
(7) Requested analytical tests ( fasting hours)
How can we achieve good laboratory practice ?
What information did she forget to take from the
patient?
How can we achieve good laboratory practice ?
The patient is suffering from chronic renal failure (dialysis) and the doctor requested the following
investigations:1. Total calcium level
2. Alkaline phosphatase
3. Intact parathyroid hormone
How can we achieve good laboratory practice ?
Sampling unit
(1)The phlebotomist took the sample following accurate sampling procedure
(2)The sample was transported to the central laboratory for processing
The patient returned back to the laboratory complaining from discrepancy between both
laboratory results?
How Can the labASSURES THE PATIENT SATISFACTION
together with
Identifying the source of error
Alkaline phosphatase
160 U/L (reference range 30-120 U/l . Mild increase in activity)
Laboratory results
Total calcium level
10.3 mg/dL (reference interval 8.4-10.5 mg/dL) Total calcium level
10.3 mg/dL (reference interval 8.4-10.5 mg/dL)
Intact Parathyroid hormone level were low 40pg/ml (16-87 pg/ml)
All the results were comparable except for the PTH it was significantly higher
500 pg/ml
Immediately after withdrawing the sample the patient went to another laboratory to repeat
the investigations
What might occur in this process that may affect the next process?
How can we achieve good laboratory practice ?
This is a problem that may face any laboratory
Why is the best approach to this problem?
How can the laboratory be confident about his results?
Where is the problem ?
Ensure your customer satisfaction by settling a firm,
well communicated patient complaint handling policy?
What is the best practice to this problem?
NEVER,NEVER LOSE A CLIENT!!
Contact his doctor to gather full clinical information about the
patient`s condition
What is the best practice to this problem?
Here comes the importance of the doctor name and contact
• PTH functions to maintain serum calcium concentrations within a tight physiologic range
• Patients with chronic renal failure develop secondary hyperparathyroidism owing to decreased renal production of 1,25-dihydroxyvitamin D, decreased Ca and hyperphosphatemia.
•These derangements in mineral metabolism stimulate PTH production to raise serum calcium and promote phosphorus excretion.
• Increased serum PTH leads to excessive bone resorption through stimulation of osteoblasts and osteoclasts
What is the clinical interpretation of this case?
•The combination of secondary hyperparathyroidism and mineralization defects (osteomalacia) represents the most common form of renal osteodystrophy (ROD).
•Subtype of ROD known as adynamic bone disease can be observed in the
setting of prolonged peritoneal or hemodialysis, over suppression of PTH with calcitriol or calcium-based phosphate binders, or the use of bisphosphonates for osteoporosis treatment
• Common biochemical hallmarks of ABD include hypercalcemia, low or inappropriately normal PTH concentrations, and reduced markers of bone turnover (e.g., alkaline phosphatase)
What is the clinical interpretation of this case?
Borderline Calcium level
Increased alkaline phosphatase
Decreased iPTH
The laboratory findings Are consistent with
Renal osteodestrophy as regards:
What is not with ROD?
Borderline Calcium level (towards hypercalcemia)
Decreased iPTH
Increased alkaline phosphatase
( it should be low due to decreased bone turnover)
The laboratory findings whichAre consistent with
Adynamic bone disease as regards:
What is not with ABD
This is a problem that may face any laboratory
Why is the best approach to this problem?
How can the laboratory be confident about his results?
Where is the problem ?
The problem has to be investigated systematically
(1) Pre-analytical
(2) Analytical
(3) Postanalytical
Where is the problem?
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•Patient related variables (drug history 2% of errors)
•Specimen related variables
Incidence of pre-analytical variables 46-68.7%
Exclude the following:
How can we achieve good laboratory practice ?
What information did she forget to take from the patients?
How can we achieve good laboratory practice? History taking
(1) Full name of the patient
(2) Age
(3) Telephone and Address of the patient
(4) Referring doctor name and address (contact)
(5) History of chronic illness
(6) History of surgeries
(7) Requested analytical tests (preparation)
The drug history..………• The patient is receiving 10 mg /day biotin
• Biotin has been reported to improve symptoms of encephalopathy and peripheral neuropathy in patients with RF and undergoing hemodialysis
• Also she is taking Ca based phosphate binders
• Vitamin D
How can we achieve good laboratory practice?
Sampling & transportation processes
(4) sample can be stored at 2-8C for 8h after collection or longer stored up to 2 month in – 20C.
What are the possible causes of error in the sampling and transportation processes?
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•Patient related variables (drug history 2% of errors)
•Specimen related variables
Incidence of pre-analytical variables 46-68.7%
Exclude the following:f
How can we achieve good laboratory practice?
Sampling & transportation processes
(1) Morning sample was taken(nocturnal rise)
(2) EDTA (filled to the desired mark on the tube as excess EDTA will interfere with the assay causing false decrease )or serum sample could be taken .
(3) Rapid collection and separation of the sample using refrigerated centrifuge to keep the sample at 2-8C.
What are the possible
causes of error in the analytical process?
How can we achieve good laboratory practice? Analytical process
1. Revise the reference interval & validation of the method
2. Apply acceptance , rejection criteria
3. Reconstitute the control or adjustor vial with accurate amount of distilled water using calibrated pipette and should be put in ice in between swirling.
4. Introduce the control, judge on the control
5. Introduce sample
How can we achieve good laboratory practice?
Analytical process
(5) Verify the result
(6) Release the report
A biotinylated anti-PTH monoclonal antibody and a ruthenium-labeled anti-
PTH monoclonal antibody form a sandwich complex with PTH
After which streptavidin-coated microparticles are added to magnetically
separate out the sandwich complex via biotin and streptavidin interaction
The principle of the method in our laboratory
Specimens with high concentrations of biotin may prevent the binding of the sandwich complex to the streptavidin-coated micro
particles, thus giving falsely low signals
Biotin is recognized as a potential interferent in PTH and
other assays that uses the same method, and it is
recommended in the product insert that samples from
patients receiving high biotin doses of >5 mg/day be
collected at least 8 h after biotin administration
The principle of the method in our laboratory
• Using another method (importance of backup plans)
• To confirm the interfering role of biotin , iPTH concentration were measured in two labs after the patient stopped taking the drug for 2 weeks (both results were the same)
•Recovery experiment using both normal and increased i PTH levels
.
HOW CAN THE LAB verify the error ?
Figure 1. Effect of biotin on serum intact PTH concentrations determined using our method. Percent recovery was calculated as the ratio of PTH concentration after the addition of biotin at various concentrations (sigma –Aldrich) (5, 10, 20, 40, 80, 160 µg/L) to the samples.( solid diamond indicates normal level& solid square indicates increased level)
This is a problem that may face any laboratory
Why is the best approach to this problem?
How can the laboratory be confident about his results?
Where is the problem ?
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Incidence of analytical errors 7-13%Confirm the following
Validation of method IQC results
EQAS results Uncertainty of measurements
Total allowable error• Revise your reference interval or establish…
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Incidence of Post-analytical variables 18-47%
Confirm the following:
Error in recording Errors in reporting
Errors in interpretations???(role of lab doctors)
Postanalytical :
No analytical validation of the test result and halting the report should be done
pre-analytical errors:Improper identification of the patient
Drug history
analytical errorsInterference and no backup plans
Conclusion……….
Data collection period I year 1 year 1 year
No. of tests 997 000 600 000 40 490
No. of patients 249 000 160 714 10 000
No. of errors 120 180 189
Frequency 0.05% of patients 0.11% of patients 0.47% of test results
Preanalytical phase 31.6% 55.6% 68.2%
Analytical phase 31.6% 13.3% overall (4.4% if referral laboratory
13.3%
Postanalytical phase 30.8% 30% 18.5%
Mulitiple phases 6%
Define the processes
The lab should standardize its operating procedures according to national or
international standards..
Put a control measures to each process.
Standardize the laboratory error detection program.
Using (process analysis, audit , questionnaires , and collection of complaints)
Accurate analysis of the errors
Finally……….
Define ways to decrease laboratory errors and to possibly avoid completely those with a real or potentially significant negative
effect on a patient’s health.
Finally……….
And here starts the improvement that should never ends………………
