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2017; 63(4):341-346
341
ORIGINAL ARTICLE
HbA1c levels in individuals heterozygous for hemoglobin variants
R
icardo
S
ilva
T
avares
1
, F
ábio
O
liveira
de
S
ouza
1
*, I
sabel
C
ristina
C
arvalho
M
edeiros
F
rancescantonio
2
,
W
eslley
C
arvalho
S
oares
1
, M
auro
M
eira
M
esquita
3
1
Undergraduate Degree in Biomedicine from Pontifícia Universidade Católica de Goiás (PUC Goiás), Goiânia, GO, Brazil
2
MD and PhD Professor at the School of Medical, Pharmaceutical and Biomedical Sciences, PUC Goiás, Goiânia, GO, Brazil
3
MSc Professor at the School of Medical, Pharmaceutical and Biomedical Sciences, PUC Goiás, Goiânia, GO, Brazil
S
ummary
Study conducted at Laboratório Clínico da
Pontifícia Universidade Católica de Goiás
(PUC Goiás), Goiânia, GO, Brazil
Article received:
7/28/2016
Accepted for publication:
10/17/2016
*Correspondence:
Laboratório Clínico da
Pontifícia Universidade Católica
de Goiás (PUC Goiás)
Address: Av. Universitária, 1.440,
Setor Universitário
Goiânia, GO – Brazil
Postal code: 74605-010
fabiogyn2009@gmail.com http://dx.doi.org/10.1590/1806-9282.63.04.341Objective:
To evaluate the levels of glycated hemoglobin (HbA1c) in patients
heterozygous for hemoglobin variants and compare the results of this test with
those of a control group.
Method:
This was an experimental study based on the comparison of HbA1c tests
in two different populations, with a test group represented by individuals
heterozygous for hemoglobin variants (AS and AC) and a control group consisting
of people with electrophoretic profile AA. The two populations were required to
meet the following inclusion criteria: Normal levels of fasting glucose, hemoglobin,
urea and triglycerides, bilirubin > 20 mg/dL and non-use of acetylsalicylic acid. 50
heterozygous subjects and 50 controls were evaluated between August 2013 and
May 2014. The comparison of HbA1c levels between heterozygous individuals and
control subjects was performed based on standard deviation, mean and G-Test.
Results:
The study assessed a test group and a control group, both with 39 adults
and 11 children. The mean among heterozygous adults for HbA1c was 5.0%,
while the control group showed a rate of 5.74%. Heterozygous children presented
mean HbA1c at 5.11%, while the controls were at 5.78%. G-Test yielded p=0.93
for children and p=0.89 for adults.
Conclusion:
Our study evaluated HbA1c using ion exchange chromatography
resins, and the patients heterozygous for hemoglobin variants showed no
significant difference from the control group.
Keywords:
glycated hemoglobin A, ion exchange chromatography, hemoglobins.
I
ntroduction
Glycated hemoglobin (HbA1c) is used to assess the effica-
cy of diabetes treatment and is a paramount control for
better quality of life among patients. The test reveals the
mean blood glucose in the last four months before the test,
based on the turnover of hemoglobin, which lasts 120
days.
1
Clinical data show that the mean level of blood
glucose in the 20 to 30 days preceding blood sampling
contributes around 50% of the end result of HbA1c, while
the mean level in the prior 90 to 120 days contributes
only 10%. Thus, this method can detect large variations
in blood glucose.
2,3
HbA1c was defined as a diagnostic method for dia-
betes mellitus, with a threshold of 6.5% for adults. The
test should be performed using a method that is certified
by the National Glycohemoglobin Standardization Pro-
gram (NGSP) and standardized or traceable to the Dia-
betes Control and Complications Trial (DCCT) reference.
4
For the measurement of HbA1c, it is desirable that
laboratories use NGSP certified methods, and it is impor-
tant to note that high-performance liquid chromatogra-
phy (HPLC) is not the only method available for the mea-
surement of HbA1c. Several other diagnostic sets that use
non-HPLC methods are also certified. The following
methods were also evaluated by the NGSP: turbidimetric
immunoassay, electrophoresis, ion exchange chromatog-
raphy and enzymatic assay.
5-8
HbA1c has several advantages over fasting glycemia,
including greater convenience, since fasting is not neces-
sary, evidence suggesting greater pre-analytical stability,
and fewer day-to-day disturbances during periods of
stress and disease.
4