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Introduction
A project for establishing com-
mon Nordic reference intervals
for 25 of the most common pro-
perties used in clinical chemistry
(table 1) was established 27
th
Mars 1998. The project was sup-
ported by The Scandinavian So-
ciety for Clinical Chemistry (NFKK)
and the project members were elected by the national
societies of clinical chemistry in the five Nordic coun-
tries: Peter Felding, Denmark (secretary), Leifur Franz-
son, Iceland, Veli Kairisto, Finland, Per Hyltoft Petersen,
Denmark, Pål Rustad, Norway (leader), Gunnar Skude,
Sweden. The project member from Sweden have since
changed first to Kristoffer Hellsing, then to Per Simonsson.
Detailed project data are presented on the project
home site (1).
General concept
Nordic laboratories were invited to participate to fol-
low this general concept:
• Contribute 3500 DKR to the project group for the
whole project.
• Collect at least 25 reference person (healthy personal
and their healthy adult family members) serum-,
plasma- and full blood samples (see “Inclusion crite-
ria”) and freeze at –80°C. The reference persons sho-
uld be evenly distributed on gender and age. Some
of the samples should be collected for analysis at the
laboratory and some for submission to a central data
bank (7 serum, 2 plasma, 1 EDTA buffy coat, each 1
mL). Each reference person should fill out a questi-
onnaire to collect relevant data for evaluation of
reference intervals.
• Receive 5 control materials on dry ice: CAL, X,
HIGH, LOW, P. CAL (with reference method values
for most properties) will be the “calibrator” of the
project and X is produced for future use with trans-
ferred target values (both are unmodified frozen
serum pools from male blood donors). HIGH (serum
pool concentrated by freeze drying) and LOW (HIGH
diluted 1:2 with an aqueous solution of sodium and
calcium) will be used to evaluate linearity of met-
hods and P (serum pool from women using oestro-
gen) as a general control with somewhat different
properties than the other pools.
• Analyse controls (ten CAL and three of each of the
other in at least one series and ten X in the rest of
the series if necessary) and samples in one series at
the laboratory. All labs were asked to analyse on
thawed samples. The labs were also encouraged to
do measurements on fresh serum and plasma with
controls in series as described above.
• Submit analytical data, method data and reference
person data to a central database.
• Reference intervals will be computed centrally.
• After project is finished, the bio- and data bank will
be administered by The Scandinavian Society for
Clinical Chemistry (NFKK).
Inclusion criteria for reference persons
The reference individual should
• be feeling subjectively healthy
• have reached the age of 18
• not be pregnant or breast-feeding
• not have been an in-patient in a hospital nor have
been subjectively dangerously ill during the last
month
• not have consumed more than 2 measures of alco-
hol (24 g) in the last 24 hours
• not have given blood as a donor in the last five
months
• not have taken prescribed drugs other than the P-pill
or estrogens during the last two weeks
• not have smoked in the last hour prior to blood sam-
pling
Sample handling
Condition of reference person
The reference person should sit at least 15 minutes
Reference intervals for 25 of the most
frequently used properties in clinical chemistry
Proposal by Nordic Reference Interval Project (NORIP)
Pål Rustad (prustad@furst.no), Fürst Medical Laboratory, Oslo
1
Nomenclature of “Committee on Nomenclature, Properties and Units (IFCC
&
IUPAC)” have been used in the text.
10
| 2 | 2003
Klinisk Biokemi i Norden
