Preanalytical Phase Quality Control
Vladimir Palicka Charles University Hradec Kralove, Czech Republic VIth National Conference of Clinical Laboratory, Borovec, Bulgaria
Preanalytical Phase The weakest point in quality management Vladimir Palicka Charles University Hradec Kralove, Czech Republic VIth National Conference of Clinical Laboratory, Borovec, Bulgaria
The influence of the laboratory on health care 60 – 70 % of the most important clinical decision-making (admission, diagnostics, discharge, medication) is based on laboratory test results
The value of laboratory testing for diagnostics and therapy Quantitative at minimum 80-90 % of all objective data are results of laboratory or other complementary departments Qualitative high quality information only are of value, the others are dangerous
To err is human: building a safer health system
Kohn LT, Corrigan JM, Donaldson MS National Academy Press, Washington, DC, 2000
Errors in medicine 10-20 % of errors negatively influence health care quality > 3 % of errors are of direct influence on patient safety „the more tests, the more errors“
Laboratory error A defect occurring at any part of the laboratory cycle, from ordering tests to reporting results and appropriately interpreting and reacting to these
ISO/PDTS 22367
negative/risky new trends in laboratory medicine influencing quality Consolidation
pre-analytical phase
Decentralization (POCT) analytical quality Outsourcing
pre- and post-analytical
Downsizing, shortages
total quality
positive trends for quality Integration of automatization and informatics improved process control Standard Operation Procedures reduction of errors in all phases Improved contact with clinicians pre- and post-analytical phase
Errors in laboratory medicine analytics approx 15 % (7-13%)
preanalytics approx 62 % (46 – 68%)
postanalytics approx 23 % (18 – 45%)
Total Testing Process Improvement prevalence of errors was reduced by automation improved laboratory technology assay standardization informatics but mostly in analytical part !
Most common reasons of pre-analytical errors Haemolysis Misidentification Sampling error (wrong tube, inappropriate amount of the sample) Clotting Sample and/or request missing Wrong patient preparation
Preanalytical errors Retrospective analysis 2001-2005 4.715.132 samples in 105 labs The most common reason for sample rejection Missing sample (37.5%) Haemolysis (29.3%) (serum 38.6%, plasma 68.4%) Alsina J: CCLM 2008, 46: 849
Prevalence of preanalytical problems Absolute prevalence
0.20 – 0.75 %
Inpatients Outpatients
0.60 – 2.80 % 0.04 – 0.30 %
Haemolysis Clotting Insufficient volume Inappropriate tube Misidentification
39.0 – 69.0 % 5.0 – 12.0 % 9.0 – 21.0 % 5.0 – 13.0 % 1.0 - 2.0 %
External Audit University Hospital 1.600 beds, all kinds of clinical medicine Big laboratory focused on biochemistry Independent body and organization Focused on preanalytical phase and cooperation with clinics Complemented by data analysis
Frequency of preanalytical errors • 5581 request in one week controlled • Daily „refuse“ frequency was 8-10 samples i.e. 0.6-1.1%
Reason for refuse Number of samples
MisWrong Time over identification sample the limit Haemolysis 26 0,47%
7 0,13%
0
14 0,25%
Sampling site Dept
ACV Hand (elbow) back % %
Collection Unknown from line site % %
A
80
20
0
0
B
80
20
0
0
C
87
8
0
5
D
100
0
0
0
E
67
33
0
0
All wards
84
12
0
4
Peculiarities during blood collection
Tourniquet time and release Dept
Released before/during first tube %
Released later than the first tube %
Tourniquet time ≤ 60 s %
Tourniquet time > 60 s %
A
0
100
0
100
B
0
100
80
20
C
19
81
38
62
D
0
100
0
100
E
33
67
0
100
84
37
63
All wards 16
Tourniquet time
Tubes correctly inverted Tube type
Correctly %
Incorrectly Not at all % %
Unknown Recommended
Coag
0
57
29
14
3-4
ESR
0
57
29
14
8-10
Serumgel
0
82
18
0
5-6
EDTA
0
78
19
3
8-10
All tubes
0
76
22
2
Time between collection and centrifugation Dept
Collection – Arrival to Lab
Collection - Centrifugation
Aver
min
max
Aver
min
max
A
60
28
93
71
47
104
B
12
2
27
19
11
34
C
24
6
116
28
18
131
D
85
85
85
100
100
100
E
34
33
36
43
42
45
All wards
30
2
116
37
11
131
preanalytical errors misidentification wrong sampling pumping with fist wet skin tourniquet time sample mixing (inverting) time for transport and centrifugation
some more preanalytical problems mislabelling
some more preanalytical problems mislabelling detection of abnormal samples
Haemolytic specimen
Lippi G: CCLM 45:728, 2007
Lipaemic specimen
Lippi G: CCLM 45:728, 2007
Icteric specimen
Lippi G: CCLM 45:728, 2007
Detection of inappropriateness Visual inspection of lipaemic, icteric and/or haemolysed samples is
highly unreliable and should be replaced by automated systems (serum indices)
Haemolysis upper „reference limit“ for free Hb plasma 20 mg/l serum 50 mg/l Visible haemolysis after centrifugation free Hb > 300 mg/l = 18.8 mmol/l (approximately 0.5% of Ery are lysed)
Haemolysis - reasons in vivo – in vitro Up to 2% samples are haemolysed At minimum 50 possible reasons inherited-acquired haemolytic anaemia haemoglobinopathias HELLP syndrome drugs, infection artificial heart valves transfusion of incompatible blood
Haemolysis â&#x20AC;&#x201C; common reasons in vivo â&#x20AC;&#x201C; in vitro Wet skin at sampling site Thin needle (usually < 21 G) Difficult venipucture Fragile veins Vacuum in tube is too high Wrong amount of blood for the amount of additive (anticoagulant)
Haemolysis - reasons Inappropriate shaking the sample Temperature discomfort High centrifugation force Long centrifugation To early centrifugation Late serum/plasma separation Wrong separation barrier Re-centrifugation of gel-tubes Pneumatic sample transporting
Haemolysis The most common reasons of the wrong samples Frequency 40 â&#x20AC;&#x201C; 70% of all rejected samples (5-times more than any other reason)
Haemolysis according dept
Lippi G, CCLM 47: 616, 2009
Haemolysis increased concentration/activity: AST, ALT, CK, LDH, lipase creatinine, urea, Fe, Mg, P, K decreased concentration/activity: ALP, GGT Alb, bilirubin, Cl, G, Na Special care: newborn bilirubin !!
Haemolysis Immunoassay False negative troponin T False increase of troponin I False increase of PSA Negative bias: testosterone, cortisol, FPIA Impossibility to measure: insulin, glukagon, CT, PTH, ACTH, gastrin
In the case of haemolysis a) Correction of result(s) b) Release of results with flags and comments c) Information of ward and new-sample request
In the case of haemolysis a) Result correction Methods with known interference (nm) rejected Release â&#x20AC;&#x17E;unaffectedâ&#x20AC;&#x153; results, only Potassium results corrected by recalculation
Should we correct the results ? Haemolysis: potassium Linear correlation Should we use the „index“ or measured concentration ? different analyzers – different indexes different calculation of corrected K = K measured – (Hb mmol/l x 5.2) K measured– (Hb mmol/l x 10) Bland-Altman: uncertainty ± 0.4 mmol/l
In the case of haemolysis a) Result correction Methods with known interference (nm) rejected Release â&#x20AC;&#x17E;unaffectedâ&#x20AC;&#x153; results, only Potassium results corrected by recalculation incorrect, error is too big ! intravascular haemolysis ?
In the case of haemolysis b) Release of results with flags and comments Many types of comments Wrong decision is quite common Credibility of lab decreases Extreme situations?
In the case of haemolysis c) Information of ward and new-sample request Nonconformity notification Laboratory book and hospital rules Quick reaction is necessary New sample request
In the case of haemolytic sample Information to ward Consultation New sample request
To err is human building a safer health system
Kohn LT, Corrigan JM, Donaldson MS National Academy Press, Washington, DC, 2000
To err is human
to delay is deadly Consumer Reports â&#x20AC;&#x201C; Health Safe Patient Project.org
System fragility Fragility of the whole system depends on Number of barriers Effectivity of barriers Emmentaler cheese effect
Error prevention High-quality sampling tubes and high quality sampling procedure Education of staff (wards and laboratory) Approved and accepted rules (Laboratory Book) TQM â&#x20AC;&#x201C; systematic error detection Quick and good cooperation with clinicians Perfect documentation of errors (and reaction!)
Preanalytical error prevention and management Wrong samples detection: - Detection system with many barriers - Information technology - Permanent monitoring of wrong samples, their numbers, reasons and places to occur
Improvement of pre-analytical phase patient identification blood collection sample handling specimen acceptance/rejection application of pre-analytical workstations (preparation, centrifugation, aliquoting, pipetting, sorting)
better communication with clinics
There is no worse loss than a lost time
Michelangelo Buonarroti (1475-1564)