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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)


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