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10 Limitations of the procedure
Assay procedures other than those specified in these instructions may yield questionable
results. Some substances may interfere with the test results; please see Section 12.
"Performance Characteristics". Test results should never be used alone, without a complete
clinical evaluation.
In conditions where the life span of red blood cells is shortened, the HbA1c results are
decreased regardless of the method used. The life span is reduced for example in conditions
such as hemolytic anemia or other hemolytic diseases, pregnancy, homozygous sickle cell
trait, iron deficiency, blood loss, polycythemia, etc. Caution with interpreting HbA1c results
in patients with these conditions is needed.
The HbA1c test should not be used to diagnose patients during pregnancy, patients that
have received cancer chemotherapy within the past 3 weeks, patients that have received a
blood transfusion within the past 3 weeks, patients with an elevated fetal hemoglobin such
as hereditary persistence of fetal hemoglobin (HPFH) or patients with a hemoglobinopathy
but normal red cell turnover (e.g. sickle cell trait). In case of rapidly evolving type 1 diabetes,
the increase in HbA1c values might be delayed compared to the acute increase in glucose
concentrations. In these conditions HbA1c value cannot be used for diagnosis of diabetes
mellitus.
The test cannot be completed if hemoglobin in the sample is out of the measuring range
(< 60 g/l).
11 Expected values
HbA1c test
result
≥ 48 mmol/mol
(or 6.5%)
39–47 mmol/mol
(or 5.7–6.4%)
< 39 mmol/mol
(or 5.7%)
12 Performance characteristics
Precision and reproducibility
A precision study was performed in line with the Clinical and Laboratory Standards Institute
(CLSI) guideline EP05-A3:2014. QuikRead go HbA1c Control and Control High, and
four venous EDTA whole blood samples were analyzed for 5 days, 2 runs per day and 2
replicates per run with 4 instruments. Precision data is summarized in Table 1. Multisite
precision was performed at 3 independent NPT clinical sites using quality control material.
The two controls were run in 5 replicates on 5 days. Multisite precision data is summarized
in Table 2.
Table 1. Precision data. CV = Coefficient of Variation. N (Number of replicates) = 80
Sample
Low
Threshold
Medium
High
Control
Control High
Table 2. Multisite precision data from 3 independent NPT clinical sites. CV = Coefficient of
Variation. N (number of replicates) = 75
Sample
Control
Control High
A precision study with finger prick samples was performed at 3 independent NPT
clinical sites. Between-site precision was analyzed from 36 patients. Three (3) operators
collected a finger prick sample from the same patient. The data is summarized in Table 3.
Table 3. Precision data of finger prick samples. CV = Coefficient of Variation. N (Number
of replicates) = 9.
Sample
Low
Threshold
Medium
High
Analytical specificity
Analytical specificity
HbA2
HbAC
HbAD
HbAE
HbAS
HbF
Acetylated Hb
Labile (pre-glycated) Hb
Interpretation of result
Indicates increased value of glycated hemoglobin (increased blood
sugar) during the previous 3 months. Cut-off used for diagnosis of
diabetes mellitus. Country-specific recommendations may vary.
Values for intermediate hyperglycaemia.
Indicates normal value of glycated hemoglobin. Does not exclude the
possibility of patient having diabetes.
Mean Value
N
(mmol/mol)
35
80
49
80
63
80
84
80
37
80
112
80
Mean Value
N
(mmol/mol)
46
75
119
75
Mean Value (mmol/mol)
7
Repeatability
SD
%CV
0.7
2.1
1.0
2.1
1.1
1.7
2.1
2.5
0.6
1.7
1.8
1.6
Repeat a -
bility
SD
%CV
SD
1.4
2.9
0.5
2.1
1.7
1.8
35
46
59
80
Significant interference (≥ 10%)
No
Yes
No
No
No
Yes (> 7%)
No
No
Within-Laboratory
Precision
SD
0.9
1.3
1.5
2.3
0.7
2.2
Between-
Reproduci-
Site
%CV
SD
1.1
1.6
1.5
2.7
CV (%)
2.3
2.7
2.7
3.7
%CV
2.6
2.6
2.4
2.7
1.9
1.9
bility
%CV
3.4
2.3
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