Guest Essay

Dr. Carmen Ricos and her colleagues have provided us with an update to their Biological Variation Database. New analytes have been added, figures have been updated and in some cases, corrected. This article summarizes all the changes made to the desirable specifications for total error, bias, and imprecision (derived from biological variation) for hundreds of analytes.

Biological variation and Desirable Specifications for QC, 2004 update

1Analytical Quality Committee, Spanish Society of Clinical Chemistry and Molecular Pathology (SEQC), 2 Laboratoris Clínics Hospital Universitari Vall d’Hebron (Barcelona), 3 Hospital de Motril (Granada), 4 Laboratori Clínic de l’Hospitalet, 5 Fundación-Hospital Alcorcón (Madrid), 6 Laboratori Clínic Manso (Barcelona), 7 Laboratori Clínic de Badalona, 8 Laboratori Clínic Bon Pastor (Barcelona), 9 Laboratori Intercomarcal Vilafranca del Penedés

• See the Database of Specifications
• See the References
• See the Reference List

This is the third edition of the analytical quality specifications for 265 analytes, derived from a database compiling articles regarding the within and between-subject biological variation (BV) components (CVI and CVG, respectively) in healthy subjects.

The first edition was presented at the Stockholm international consensus conference on Strategies to Set Global Analytical Quality Specifications in Laboratory Medicine and was published in the Scan J Clin Lab Invest 1999;59:475-586. It was also published on this website in June 2000. The second edition appeared at the end of 2001 in this website and was published in Spanish at http://www.seqc.es/. This third edition compiles all works retrieved until December 2003 and is also available in Spanish at the above mentioned web-site.

The 2004 update includes 4 new analytes and contains several corrections and additions with respect to the second edition. All the changes are listed here in alphabetical order.

• Alpha-fetoprotein in serum: this is a new analyte (first paper published on BV in 2003)
  
• Acid phosphatase, tartrate resistant: a typo in the previous edition has been amended
  
• Alkaline phosphatase, bone isoform: a typo in the previous edition has been amended.
  
• Alkaline phosphatase, liver: a new paper has appeared since the previous edition, resulting in a change in the median BV values
  
• C -Telopeptide type I collagen (s-CTx) in serum and urine: a paper from 1998 was recently found and added to this database (reference 184), resulting in small changes in the median BV values.
  
• Carcinoembrionic antigen: a new paper, reference 185, has been added. The resulting median value for CVI is higher than that in the previous edition.
  
• Cyfra 21.1 in serum: this is a new analyte (first paper published on BV in the 2003). It does not refer to healthy subjects, but instead to non-small-cell lung carcinoma. However, it has been included in the update to provide an approximation of the BV values for this analyte.
  
• Dehydroepiandrosterone sulfate: a typo in the previous edition has been amended.
  
• Deoxypiridinoline/Creatinine, 24 h: a typo in the previous edition has been amended.
  
• Estradiol (serum and urine): a typo in the previous edition has been amended.
  
• Follicle stimulating hormone (FSH): a typo in the previous edition has been amended.
  
• Glucose in serum: a new paper appeared in 2002 (reference 186), resulting in minor changes in the median BV values
  
• Hemoglobin A1C in blood: all values included in the previous editions under the name “glycohemoglobin” have been added to those compiled under the name “hemoglobin A1C” to unify the terminology. A new article published in 2002 (reference 186) has been added. Moreover, several papers dealing with diabetic patients, which had been erroneously included in the previous version, have been now eliminated. This change has decreased the median CVI and CVG values.
  
• N-Telopeptoide type I collagen/creatinine in urine: an article from Paget syndrome has been eliminated and, therefore, the median values presented here are lower than those in the second edition.
  
• Riboflavin in blood-erythrocyte: a mistake in the previous edition quoted this analyte as a serum component instead of as a blood-erythrocyte component.
  
• Sodium bicarbonate: this analyte was left out of the previous editions and has now been included.
  
• Sodium chloride in sweat: this is a new analyte (first paper published in 2002)
  
• Soluble CD165 in plasma:this is a new analyte (first paper published in 2003)
  
• Thyroid stimulating hormone (TSH): a typo in the previous edition has been amended.
  
• Thyroxine (T4): mistakes in the previous edition, which included a paper with a CVI of zero as well as a typo for CVG, have been amended. Thus, the resulting CVI and CVG values are lower than those in the previous edition.
  
• Triiodothyronine (T3): a typo for the CVG in the previous edition has been amended.
  
• Vitamin B12: was quoted as Riboflavin in the previous edition.
  
• Vitamin B6: the CVI and CVG values and the corresponding quality specifications were erroneously left out of the previous edition and have been quoted here.