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Guest Essay

Biologic Variation and Desirable Specifications for QC, 2006 Update

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.

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,
10 Servei de Bioquímica Hospital Germans Trias i Pujol (Badalona)

This is the fourth edition of the analytical quality specifications for 289 analytes, derived from a database compiling articles on 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 and third edition appeared at the end of 2001 and 2003, respectively on this website and were also published in Spanish at http://www.seqc.es.

This fourth edition has the following changes with respect to the previous edition:

  • a-amylase: articles with values from non-healthy subjects have been eliminated, thus resulting in lower within and between-subject biological variation estimates: CVI from 9.5% to 8.7% and CVG from 29.8% to 28.3%.
  • a-carotene: analyte included in this edition because the first paper appeared in 2005
  • a-Tocopherol: analyte included in this edition because data were found recently
  • Amyloid A: a paper describing values for within and between-subject biological variation for this analyte was just found and results are incorporated in this fourth edition for the first time.
  • Ascorbic acid (Vitamin C): a paper from 1994 was just found and results have been added
  • ?-carotene: analyte included in this edition because the first paper appeared in 2005
  • C reactive protein: one paper published in 2005 has been added, thus lowering the median value compared with that published in the third edition.
  • Endothelial growth factor: a paper describing values for within and between-subject biological variation for this analyte was published in 2005 and has been incorporated in this fourth edition.
  • d-aminolevulinic acid: analyte included in this edition because the first paper appeared in 2005
  • Endothelial growth factor: analyte included in this edition because the first paper appeared in 2005
  • Free carnitine: a paper describing values for within and between-subject biological variation for this analyte was found and the analyte has been incorporated in the fourth edition.
  • Lutein: analyte included in this edition because the first paper appeared in 2005
  • Lycopene: analyte included in this edition because the first paper appeared in 2005
  • Lymphocyte CD4: analyte included in this edition because the first paper appeared in 2005
  • Porphobilinogen: analyte included in this edition because the first paper appeared in 2005
  • Porphyrins: analyte included in this edition because the first paper appeared in 2005
  • Prostate-specific antigen (PSA): a new paper from 2005 has been added. Also, data from prostate cancer patients have been eliminated. This amendment caused higher CVI values compared with the 2003 edition CVI from 14.0% to 18.1%
  • Retinol: analyte included in this edition because the first paper appeared in 2005
  • Semen concentration, morphology, motility and vitality: a paper was found describing values for within- and between-subject biological variation for this analyte and it has been incorporated in the fourth edition.
  • Total carnitine: a paper describing values for within and between-subject biological variation for this analyte was found and they have been incorporated in the fourth edition for the first time.
  • Vitamin B1: analyte included in this edition because the first paper appeared in 2005
  • Vitamin B2 (Riboflavin): analyte included in this edition because the first paper appeared in 2005
  • Vitamin B2, state: this analyte appeared in 2003 with the erroneous name of Vitamin B2.
  • Vitamin B6: analyte included in this edition because the first paper appeared in 2005
  • Vitamin B6, state: this analyte appeared in 2003 with the erroneous name of Vitamin B6
  • Vitamin E (?-Tocopherol): analyte included in this edition because the first paper appeared in 2005
  • Vitamin K (Phylloquinone): analyte included in this edition because the first paper appeared in 2005