Immunophenotyping is an important diagnostic
tool for decision making in various diseases. Although
clinical interpretation relies on measurable aberrations
of the patient’s values from normal ranges, agedependent
are rarely available. Materials and Methods:
The present study is aimed to combine published data
about normal values of peripheral blood lymphocyte
subpopulations to describe age-dependent changes from
the neonate to the adult. These values could serve in a
better way as normal values in comparison to present
ones. Furthermore, this investigation allows us to define
valid data even for short periods in children’s life and to
investigate the influence of technical approaches, sample
preparation, antibody selection, measurement equipment,
and data analysis. Results: Development-related
alterations of lymphocyte subset counts in children could
be extracted from the pre-existing papers for diagnostic
use. These results were mostly independent from gender,
ethnic factors, procedure of sample collection, anticoagulation,
pre-analytical procedures, time to workbench,
applied method for immunophenotyping, staining
procedure, selected monoclonal antibodies, technical
devices, and software products. Conclusion: Our data
indicate that previous normal values are not sufficiently
precise for the interpretation of lymphocyte subsets in
children. Mainly during the 1st year of life, count and
subset distribution of lymphocytes is different from that
of adults. Therefore, a close meshed data set of normal
values is required to guarantee adequate diagnostic
interpretation.