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Klinisk Biokemi i Norden · 2 2017
were wider for fasting than for nonfasting triglyce-
rides, which is explained by regression dilution bias
as the initial groups were made based on nonfasting
concentrations and then fasting concentrations were
compared afterwards. Thus, if groups were made
initially based on fasting concentrations, then the
confidence intervals for nonfasting triglycerides were
wider than for fasting triglycerides (data not shown).
In other words, the variation in fasting and nonfas-
ting triglyceride concentrations measured in the same
individuals at two different occasions are similar, as is
also clear for the value in all 5538 individuals combi-
ned (Figure 4, top). Results were also similar for LDL
cholesterol comparing nonfasting and fasting values
(Figure 4, bottom).
Recommendations on laboratory reporting of
abnormal nonfasting and fasting lipid profiles
We recommend laboratory reports should flag abnor-
mal values based on desirable concentration cut-
points, defined by guidelines and consensus state-
ments
13-17
, and for nonfasting samples flag abnormal
concentrations as triglycerides ≥2mmol/L(175mg/
dL)
36,37
(corrected for endogenous glycerol), total
Table 3. Abnormal plasma lipid, lipoprotein and apolipoprotein concentration values that should be flagged in laboratory
reports based on desirable concentration cut-points.
Abnormal concentrations
Nonfasting
Fasting
mmol/L mg/dL§
g/L
mmol/L mg/dL§
g/L
Triglycerides*
≥2
≥175
≥1.75
≥1.7
≥150
≥1.50
Total cholesterol
≥5
≥190
≥1.90
≥5
≥190
≥1.90
LDL cholesterol
≥3
≥115
≥1.15
≥3
≥115
≥1.15
Remnant cholesterol**
≥0.9
≥35
≥0.35
≥0.8
≥30
≥0.30
NonHDL cholesterol‡
≥3.9
≥150
≥1.50
≥3.8
≥145
≥1.45
Lipoprotein(a)
‡‡
≥50†
≥0.50
‡‡
≥50†
≥0.50
Apolipoprotein B
≥100
≥1.00
≥100
≥1.00
HDL cholesterol††
≤1
≤40
≤0.40
≤1
≤40
≤0.40
Apolipoprotein A1
≤125
≤1.25
≤125
≤1.25
These values for flagging in laboratory reports are in some instances higher than corresponding to recommended desirable values
in high and very high risk patients. We recommend to use SI units (e.g. mmol/L for lipids and g/L for apolipoproteins); however, as
these values are not used in all countries, we also provide cut-points for other commonly used units.
* Triglyceride cut-points based on assays with correction for endogenous glycerol. In most laboratories, however, trigly-
cerides are measured without subtraction of the glycerol blank; thus, triglycerides may wrongly be flagged as abnormal
in rare individuals with very high plasma glycerol. That said, not accounting for the glycerol blank in outpatients rarely
affected the triglyceride concentration more than 0.1 mmol/L; in inpatients the effect was rarely over 0.28 mmol/L
39
. High
endogenous glycerol is seem e.g. during intravenous lipid or heparin infusion.
** Calculated as total cholesterol minus LDL cholesterol minus HDL cholesterol, that is, VLDL, IDL and chylomicron rem-
nants in the nonfasting state and VLDL and IDL in the fasting state.
‡ Calculated as total cholesterol minus HDL cholesterol.
‡‡ There is no consensus on which cut-point value in nmol/L that should be used for lipoprotein(a).
† Value for lipoprotein(a) should represent ≥80
th
percentile of the specific lipoprotein(a) assay.
†† Sex specific cut-points can be used for HDL cholesterol
§Values in mmol/L were converted to mg/dL by multiplication with 38.6 for cholesterol and by 88 for triglycerides, followed
by rounding to nearest 5 mg/dL; for total cholesterol we used 5 mmol/L and 190 mg/dL, as these are the two desirable concen-
tration cut-point typically used in guidelines.
LDL=low-density lipoprotein. HDL=high-density lipoprotein. VLDL=very low-density lipoprotein. IDL=intermediate-
density lipoprotein.
