Ann Lab Med.  2012 Sep;32(5):345-354. 10.3343/alm.2012.32.5.345.

New Decision Criteria for Selecting Delta Check Methods Based on the Ratio of the Delta Difference to the Width of the Reference Range Can Be Generally Applicable for Each Clinical Chemistry Test Item

• Park SH
• Kim SY
• Lee W
• Chun S
• Min WK

• KMID: 1387349
• DOI: http://doi.org/10.3343/alm.2012.32.5.345

Abstract

BACKGROUND
Many laboratories use 4 delta check methods: delta difference, delta percent change, rate difference, and rate percent change. However, guidelines regarding decision criteria for selecting delta check methods have not yet been provided. We present new decision criteria for selecting delta check methods for each clinical chemistry test item.
METHODS
We collected 811,920 and 669,750 paired (present and previous) test results for 27 clinical chemistry test items from inpatients and outpatients, respectively. We devised new decision criteria for the selection of delta check methods based on the ratio of the delta difference to the width of the reference range (DD/RR). Delta check methods based on these criteria were compared with those based on the CV% of the absolute delta difference (ADD) as well as those reported in 2 previous studies.
RESULTS
The delta check methods suggested by new decision criteria based on the DD/RR ratio corresponded well with those based on the CV% of the ADD except for only 2 items each in inpatients and outpatients. Delta check methods based on the DD/RR ratio also corresponded with those suggested in the 2 previous studies, except for 1 and 7 items in inpatients and outpatients, respectively.
CONCLUSIONS
The DD/RR method appears to yield more feasible and intuitive selection criteria and can easily explain changes in the results by reflecting both the biological variation of the test item and the clinical characteristics of patients in each laboratory. We suggest this as a measure to determine delta check methods.

Keyword

Delta check; Detection methods; Reference range; Decision criteria

MeSH Terms

Alanine Transaminase/blood
Alkaline Phosphatase/blood
Aspartate Aminotransferases/blood
Bilirubin/blood
Blood Urea Nitrogen
Chemoembolization, Therapeutic
Clinical Chemistry Tests/methods/*standards
Creatine/blood
*Decision Trees
Humans
Reference Values
Renal Dialysis
Uric Acid/blood

Figure

• 

  Fig. 1 Schematic diagram of the procedure for the determination of decision criteria for delta check method selection. Abbreviations: ADD, absolute delta difference; DD, delta difference; RR, reference range; In, inpatients; Out, outpatients; TACE, transarterial chemoembolization; HD, hemodialysis.

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