Klinisk Biokemi i Norden · 2 2017
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cholesterol ≥5mmol/L(190mg/dL), LDL cholesterol
≥3mmol/L(115mg/dL), calculated remnant choles-
terol ≥0.9mmol/L(35mg/dL), calculated nonHDL
cholesterol ≥3.9mmol/L(155mg/dL), HDL choles-
terol ≤1mmol/L(40mg/dL)(sex specific cut-points
can be used for HDL cholesterol), apolipoproteinA1
≤1.25g/L(125mg/dL), apolipoproteinB ≥1.0g/L(100mg/
dL), and lipoprotein(a) ≥50mg/dL(80
th
percentile)
(Table 3); for fasting samples abnormal concentra-
tions should be triglycerides ≥1.7mmol/L(150mg/
dL), remnant cholesterol ≥0.8mmol/L(30mg/dL), and
nonHDL cholesterol ≥3.8mmol/L(145mg/dL) while
other measurements should use identical cut-points
as for nonfasting values.
Usually, in laboratory medicine results of measu-
red parameters are considered to be abnormal if they
exceed the age- and sex-specific reference interval
(=2.5
th
to 97.5
th
percentiles). All results below or above
these recommended cut-points are flagged with a
character to show at a glance that this value deserves
attention. Also automatic validation and flagging are
used in many laboratories. Depending on the labora-
tory, this labelling can vary. Theoretically the reference
intervals should be established by each laboratory,
but in most cases they are taken over from the gene-
ral information provided by the manufacturer in the
package insert. Due to wide-spread unhealthy life style,
in most populations the upper reference cut-point (i.e.,
97.5
th
percentiles) of total cholesterol (>7.8 mmol/L in
Denmark) and LDL cholesterol (>5.5 mmol/L) as well
as triglycerides (>4.4 mmol/L) are very high and place
individuals at considerably increased cardiovascular
risk. Therefore, flagging abnormal values based on
desirable concentration cut-points rather than refe-
rence intervals are recommended to identify abnor-
mal test results. Especially for LDL cholesterol the
desirable values vary with the individual’s global risk
between <1.8 mmol/L(70mg/dL)(very high risk), <2.5
Figure 4. Comparison of concentrations of
plasma triglycerides and LDL cholesterol
measured in the nonfasting and fasting
states in the same patients. Diabetes was
determined as a hemoglobin A1c >7.1%
(of all 5538 patients with both fasting and
nonfasting triglyceride measurements, 371
did not have a hemoglobin A1c measure-
ment). Values are medians and interquartile
ranges; in strata of plasma triglycerides, the
interquartile ranges are larger for fasting
than for nonfasting values, which is explai-
ned by regression dilution bias as the groups
were defined initially based on the nonfast-
ing measurements. Figure designed by Prof
B. G. Nordestgaard and Dr A. Langsted
based on unpublished data on patients from
Herlev and Gentofte Hospital, Copenhagen
University Hospital in the period 2011
through 2015.
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
LDL cholesterol, mmol/L
All
>4.0 175
Diabetes
No
4711
Yes
418
N
1.6-2.5 1454
2.6-4.0 534
Triglycerides, mmol/L
Triglycerides, mmol/L
5538
<1.1 1793
1.1-1.5 1582
All
>4.9 149
Diabetes
No
3066
Yes
622
N
2.5-2.9 761
3.0-4.9 1482
LDL, mmol/L
4141
<1.8 800
1.8-2.4 949
Nonfasting
Fasting
Nonfasting
Fasting
Figure 4
