PMID- 10620576
OWN - NLM
STAT- MEDLINE
DCOM- 20000302
LR  - 20190722
IS  - 0009-9147 (Print)
IS  - 0009-9147 (Linking)
VI  - 46
IP  - 1
DP  - 2000 Jan
TI  - Causes of unsatisfactory performance in proficiency testing.
PG  - 89-99
AB  - BACKGROUND: Proficiency testing (PT) provides a measure of the effectiveness of 
      laboratory quality assurance programs. Test reports are released from processes 
      that the laboratory judges to be in conformance with quality specifications; an 
      evaluation of unsatisfactory performance (UNSAT) by a PT provider is an 
      unexpected outcome for the laboratory. An understanding of the root cause(s) of 
      testing errors provides an opportunity for the continuous improvement of 
      laboratory services. METHODS: We used participant data from the New York State 
      Department of Health PT program to characterize the quality of testing in the 
      toxicology specialty. Outcomes from laboratory investigations into causes of 
      UNSAT and information on quality control practices collected from all program 
      participants were used to identify the root causes of error. RESULTS: Two classes 
      of error were encountered: spurious test results caused by lapses in standard 
      operating procedures and instrument malfunctions (300 per million assays) and 
      common-cause analytic error (7000 per million assays or 0.7% rate of UNSAT). 
      Causes of spurious results included inaccurate mathematical correction for 
      specimen dilution, misinterpretation of instrument codes, and instrument sampling 
      errors. Calibration drift was most frequently cited as the common-cause analytic 
      error. Approximately one-half of the laboratories used an allowable error for the 
      quality control of analytical systems that exceeded the threshold error specified 
      by manufacturers for stable instrument performance. CONCLUSIONS: The causes of 
      spurious results suggest the need for ongoing competency testing of analysts 
      where analyst intervention is required in an otherwise automated process, and for 
      continued diligence in mistake-proofing instrument design. The intrinsic quality 
      of laboratory testing is unlikely to improve until the allowable error in quality 
      control is consistent with manufacturer specifications for stable system 
      performance.
FAU - Jenny, R W
AU  - Jenny RW
AD  - Laboratory for Molecular Diagnostics, Division of Molecular Medicine, Wadsworth 
      Center, New York State Department of Health, Albany, NY 12201-0509, USA. 
      jenny@wadsworth.org
FAU - Jackson-Tarentino, K Y
AU  - Jackson-Tarentino KY
LA  - eng
PT  - Journal Article
PL  - England
TA  - Clin Chem
JT  - Clinical chemistry
JID - 9421549
SB  - IM
CIN - Clin Chem. 2000 Jan;46(1):7-8. PMID: 10620565
CIN - Clin Chem. 2000 Jan;46(1):132. PMID: 10620586
MH  - Clinical Chemistry Tests/instrumentation/*standards
MH  - Data Interpretation, Statistical
MH  - Drug Monitoring/instrumentation/*standards
MH  - Humans
MH  - New York
MH  - Quality Control
MH  - Toxicology/*standards
EDAT- 2000/01/06 09:00
MHDA- 2000/03/04 09:00
CRDT- 2000/01/06 09:00
PHST- 2000/01/06 09:00 [pubmed]
PHST- 2000/03/04 09:00 [medline]
PHST- 2000/01/06 09:00 [entrez]
PST - ppublish
SO  - Clin Chem. 2000 Jan;46(1):89-99.