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Klinisk Biokemi i Norden · 3 2019
The EFLM Biological Variation Database
Aasne K. Aarsand
1
, Sverre Sandberg
2
1
Chair of the EFLM Working Group on Biological Variation
2
Chair of the EFLM Task Group on the Biological Variation Database
Biological variation (BV) data have a number of
important applications in laboratory medicine and
are commonly used e.g. for setting analytical per-
formance specifications. However, many studies on
BV are several decades old, and different studies have
delivered widely varying BV estimates for the same
measurand. Thus, concern has been raised regarding
the reliability and robustness of available BV data and
the consequences of using these data in diagnosis
and monitoring.
Following the 1st Strategic Conference of the EFLM
defining Analytical Performance Specifications in
November 2014, the Task (and Finish) Group for the
Biological Variation Database (TG-BVD) was esta-
blished. The TG-BVD has, in collaboration with the
EFLMWorking Group on BV (WG-BV), developed a
standard for evaluating studies on BV; th
(1), a Minimum Dataset for BV studies and a meta-
analysis approach for delivery of global BV estimates
and are using these tools to deliver the EFLM Biolo-
gical Variation Database.
The EFLM Biological Variation Database, available
via the EFLM homepage and at
was launched during the Euromedlab in
Barcelona in May 2019. It aims to deliver updated,
evidence-based BV estimates to users worldwide.
To populate the database, systematic literature
searches are performed for the measurands under
review, and relevant publications are appraised by
the BIVAC. The BIVAC is designed to assess the
quality of BV publications by verifying whether all
essential elements that may impact upon veracity and
utility of the associated BV estimates are present and
consists of 14 quality items. Based on the individual
scores for each of these, an overall grade A, B, C or D
is set for the publication under review, with studies
receiving a D grade being considered unfit for use in
clinical practic.
At the launch, over 1500 BV data sets for more than
130 measurands and close to 500 publications were
already included in the database. The database is free
for use and results from appraised studies, including
the BV Minimum Dataset and the BIVAC scores, are
available for review.
To deliver global BV estimates, meta-analysis is
performed for BIVAC compliant studies with similar
study characteristics, with the BIVAC grade and the
width of the BV estimate confidence interval being
used as weights in a weighted median approach.
Global estimates were at the launch available for 80
measurands, with quality review and appraisal of
new measurands being continuously ongoing. Meta-
analysis results for additional measurands will be
included once the review and appraisal process for
the measurand in question is finalized.
For the future, a number of developments are
planned, such as automatic calculations of analytical
performance specifications, improvements to the user
interface with sign-up for updates and delivery of
meta-analysis results for subgroups/different samp-
ling intervals.
1. Aarsand AK, Roraas T, Fernandez-Calle P, Ricos
C, Diaz-Garzon J, Jonker N, et al. The Biological
Variation Data Critical Appraisal Checklist: A
standard for evaluating studies on biological
variation. Clin Chem 2018;64:501-514.
