Improving Medical Performance and Patient Diagnosis in

Improving Medical Performance and Patient
Diagnosis in the Clinical Laboratory
RSLM Targu Jiu September 2010
Trefor Higgins, MSc, FCACB - Director of Clinical Chemistry,DynaLifeDx
Cristina Florescu MD, MSc, EurClinChem-Country Manager, SCL
Patient/Laboratory Encounters
• 35% of Albertans had 1 encounter with
the laboratory in the past year.
• 81% were satisfied with the level of
service and access to testing.
Topic #1
Clinical Laboratory Environment
Romania versus Canada
CANADA:
• 6 provinces officially do not have private
laboratories
• 4 have private laboratories
• 1 is trying to purchase all private labs
• 1 denies existence of private labs
Topic #1
Clinical Laboratory Environment
Romania versus Canada
ROMANIA:
• 2500 laboratories in total
• 440 public labs
• 2100 private labs
Topic #1
Clinical Laboratory Environment
Romania versus Canada
CANADA:
• Ownership of private laboratories is not
restricted
• Must have Medical Director (MD)
• Department Directors need not have MD
ROMANIA:
• Ownership of private labs is not restricted
• Must have MD, Biologist or Biochemist
degree
Topic #1
Clinical Laboratory Environment
Romania versus Canada
CANADA:
• All laboratories must be accredited by
provincial College of Physicians and
Surgeons
ROMANIA:
• Laboratories would be nice to have
accreditation of RENAR;
• ISO 17025 and 15189 have been
implemented in 70% private labs and 30%
public labs
Cost of Laboratory Services
in Alberta
• 3.5 to 5% of all healthcare expenditures
• Switzerland 11.4%
• United Kingdom 5%
Cost of Medicine Healthcare
in Romania
• 3.6 to 4% of all healthcare funds from PIB
(2.2.billion lei)
• Laboratory costs: one of the lowest
percentage
• Civilized countries:5,5-10.5%
Topic #2
The role of the clinical laboratory for clinicians
and patients
Topic #2
Importance
of Laboratory Services
• 60-70% of diagnoses based on laboratory
tests
• 70% of objective data in a patient file is lab
data
• 70 to 80% of healthcare decisions involve
1 or more laboratory investigations-NHS
report
Topic #2
Purpose of Testing
• Diagnosis
– Confirmation or rejection of clinical diagnosis.
• Prognosis
– Information Regarding likely outcome of disease.
• Monitoring
– Follow natural history or response to treatment.
• Screening
– Detection of sub clinical disease.
Topic #2
The role of the clinical laboratory for clinicians
and patient diagnoses:
Shift from clinical to laboratory-based diagnosis
Topic #2
Shift in Diagnosis to
Laboratory
• Diabetes -
glucose or HbA1c
• MI -
troponin
• Thyroid -
TSH
Topic #2
Shift in Expectations
• hCG:
need to know pregnancy status
»prior to DI
»IVF
• gene testing
Topic #2
The role of the clinical laboratory for clinicians
and patient diagnoses:
Romania:
•1997 - The Law no.145 of Health Insurance
•1998-1999 - Establishment of the National
House Of Health Insurance (CNAS)
•1999 – “change” in mentality-laboratory the most flexible
segment
Shift from public to private system for laboratory activity
•Shift from clinical to laboratory-based diagnosis
•After 2000- Involvement of laboratory in clinical trials
Topic #3
Errors in Laboratory Testing
• what to avoid
• where to pay attention
Topic #3
Indiscriminate Testing
Tests/requisition:
urban
rural
11.7
4.9
– Urinalysis is counted as one test
– Complete blood count is counted as one test
– Chemistry profiles cannot be ordered
Topic #3
Over utilization - - Indiscriminate Testing
a) 208 mL of blood for 42 tests - Internal
Medicine
b) 550 mL of blood for 125 tests - Intensive
Care Unit
c) Iatrogenic pediatric anemia
d) 180 mL of blood for lab testing in 50% of
patients receiving transfusion
Topic #3
Over utilization
- Increased Patient Demand
Informed public due to:
a) public policy (Know your Cholesterol
program)
b) special interest groups (PSA)
c) Internet access
Topic #3
Misunderstanding
Laboratory Results
• the reference range
• the Ulysses syndrome
• Critical Difference theory
• analytical problems
Topic #3
The Reference Range
Ca++
2.64 H (2.10 - 2.60 mmol/L)
2.5% population > 2.60
2.5% population < 2.10
age specific -alk phos
sex specific - creatinine
Topic #3
The Ulysses Syndrome:
Ill effects of extensive diagnostic
investigations due to a false positive or
wrongful interpretation of results in the
course of routine laboratory screening.
Topic #3
Pre-analytical variables:
PATIENT:
age (alk phos)
sex (hemoglobin)
medications (coumadin & INR)
SAMPLE:
quality, labeling, transport, temp
proper collection technique
tube, hemolysis (K+), dilution (CBC)
Topic #3
Pre-analytical variables:
1. diurnal:
2.
3.
4.
5.
cortisol/Fe high am, low pm
posture:
calcium higher on standing
sample type: K+ lower in plasma than serum
time of year: trig. high in spring/HbA1c
higher in winter
pregnancy: electrolytes
Topic #3
Case Study
72 y male has serum K+ collected at 0830 at PCC. K+
is 6.2 mmol/L. Physician phones and tells patient to go
to Emergency Room. On a sample collected at 1630,
K+ result from hospital lab is 4.2 mmol/L on plasma.
Case Study Conclusion:
• One lab cannot perform K+ tests with any accuracy
or
• Thromboctyopenia
or
• Interference – ACE inhibitors increase serum K.
Topic #3
Critical Difference Theory: When a
result is clinically different than previous
result.
Critical difference =
C = Z x √2 x √Cbiological + Canalytical
2
2
Topic #3
Calculated Critical Differences for
Some Chemistry Parameters
TEST
Glucose
Cholesterol
Uric Acid
Urea
Total Protein
Albumin
Calcium
In Phosphorus
T. Bilirubin
Alk Phosphate
LD
AST
BIOLOGICAL
CV
4.7
5.8
8.6
10.3
2.6
2.6
1.6
4.8
16.5
6.5
12.9
8.2
ANALYTICAL
CV
1.9
2.0
3.0
1.6
3.1
3.1
1.5
1.3
4.7
3.6
1.5
5.7
CD AS %
9.9
17.0
25.2
28.9
11.2
11.2
6.1
13.8
47.5
37.1
35.0
27.7
Topic #3
Case Study
57 y female has a TSH ordered as part of a
yearly physical. The result is 6.62 mU/L
(reference range 0.2 – 4.0 mU/L). Before
commencing therapy with Synthyroid, the
physician orders another TSH. This time the
result is 3.1 mU/L.
To treat or not to treat
Topic #3
TSH analytical variation
TSH biological variation
10%
19%
Total variation (critical difference)
62%
First TSH result
CD =
6.62 x 0.62 = 4.1
∴ 2nd result of 3.1 is within critical difference
(6.62 – 4.1) of first result
Thyroid Algorithm
Topic #3
TSH
< 0.2 mIU/L
0.2 - 6.1 mIU/L
no further testing
6.1 - 18.0 mIU/L
fT4
fT4
abnormal
no further testing
normal
fT3
Topic #3
Requesting all
Thyroid Tests
• 2% of all thyroid test requisitions
•
•
request every available test.
2000 patients’ thyroid results where all
tests were ordered were reviewed.
1 potentially useful result not provided
by algorithm.
Topic #3
Pitfalls in analysis:
what you get is not what it is
Topic #3
HAMA
• heterophile anti-mouse antibody
• especially in rural populations
Lab A
Lab B
TSH mIU/L
27.6
0.04
fT4 pmol/L
34.8
34.8
Jury Awards $16.2M in Diagnosis Case
Topic #3
Topic #3
Problems with
Jennifer Rufer Case
• Inappropriate use of test
• No confirmation of test
• No clinical support
Topic #3
Residual tissue can produce same hCG
pattern as heterophile antibody.
Topic #3
Ascorbic acid can lower/raise:
cholesterol
glucose
urate
Topic #3
M- protein, especially IgM, can
interfere with assay results:
•Glucose
•Electrolytes
•Bilirubin
•GGT
•Ferritin
Topic #3
Pre-analytical in laboratory services for
clinical trials:
•Too much blood required by study protocols
for laboratory tests(e.g.7 ml blood for CBC
versus 2ml needed, 10 ml blood for safety
chemistry versus 4 ml needed)
•Missing/incomplete data on RF
•Sometimes, investigators do not protect the
patient confidentiality
Topic #3
Case study
•
Patient enrolled
for CT no. X, SCR visit,
identified by barcode,
but investigator sent
RF where revealed the
identity of the patient
Topic #3
Case study
•Patient has to collect urine
samples for 6 weeks, in
consecutively days, store them
at study site and send them to
laboratory for testing urinary
pregnandiol
Laboratory provided RF + SK ,
designed visit specific
The samples were collected
using wrong sampling kit
Patient mixed up the collection
weeks, and also
within a week, the dates of
collection
Topic #3
Post-analytical
1) Report.
Correct information on correct patient to
correct physician in a timely manner.
2) Interpretation of result.
Topic #3
Post-analytical
Reporting errors - when using IT
communication channels to send the results.
This usually affect TAT for reporting lab
parameters and sometimes may influence the
investigator’s decision regarding which step to
follow in the patient treatment with the study
medication
Topic #3
Post-analytical
Topic #3
Post-analytical
Topic #3
Post-analytical
Summary
• The laboratory plays an important role
in diagnosis.
• Laboratory resources are finite and
should not be overused.
• Many factors affect laboratory results.