Establishing referance intervals for haematological parameters, soluble serum
transferrin receptor and serum transferrin in a tertiary hospital in Malaysia
Shanmugam Hemalatha, Kumariah Thatcheiany and Sthaneshwar Pavai
Department of Pathology, University Malaya, Kuala Lumpur, Malaysia
Background
Clinical laboratory testing is an integral part of diagnosis, treatment and
prognosis that ensures quality and effective healthcare. Factors like genetics,
dietary intake, gender, age, level of physical activity, altitude above sea level etc.
can alter biochemical and haematological parameters in a population Variation can
also occur based on the instrument or methodology being used. Thus it is pivotal
for laboratories to establish their own reference intervals specific for their
population.
In our laboratory we have been interpreting CBC results based on the
reference value established for the western population. In the context above, we
decided to establish our own reference value by studying healthy Malaysian adults.
Iron deficiency is also a common clinical problem in our population. Its distinction
from anaemia secondary to infection, inflammation or malignancy remains a
clinical challenge. The conventional laboratory tests of iron status are influenced by
several factors but additional markers such as serum transferrin and serum soluble
transferrin receptor helps in better evaluation of iron status.
The aim of this study was to determine reference interval for haematology
parameters and serum iron markers that includes serum soluble transferrin
receptor and serum transferrin.
Materials and methods
Blood samples were collected from healthy volunteer blood donors at
Transfusion Medicine Department, University Malaya Medical Centre aged between
18-60 years. A total of 391 samples were collected, of which 202 samples were
from males and 179 sample were from females. The criteria that was used to
exclude subjects from our study were mean corpuscular haemoglobin (MCH) < 25
pg and serum ferritin < 15 ug/L. According to the criteria above and after excluding
outliers, 255 subjects were included in our study (male 132 and female 123).
The analysis was conducted at Division of Laboratory Medicine, University
Malaya Medical Centre. Samples for full blood count were collected in 3 ml K2
EDTA (Beckton and Dickinson) tubes and serum assay in 5 ml plain tubes (Beckton
and Dickinson). The full blood counts were analysed within 4 hours of collection by
Sysmex XE5000 (SYSMEX Corporation, Kobe).The serum iron and ferritin were
analysed within the same day of collection. Remaining serum for transferrin and
soluble serum transferrin receptor were stored at -70oC until analysis at a later date.
Samples were thawed only once before testing. Serum iron, serum soluble
transferrin receptor and serum transferrin were assayed spectrophotometrically by
Dimension Vista 1500 (Siemens Healthcare Diagnostics) and the serum ferritin was
measured by chemiluminescence technique using Advia Centaur XP (Siemens
Healthcare Diagnostics).
The linearity and precision for serum soluble transferrin receptor and
serum transferrin were verified and were within manufacturer’s claims.
Data was analysed using Statistical Package for Social Sciences version
20.0. Reference interval value, mean and standard deviation were calculated for
each parameter. Normality of these data was checked by box plot and KolmogorovSmirnov test. Independent t-test and Mann-Whitney U test was performed to detect
statistical difference between both genders.
Results
Table 1: Reference interval with their 90 % confidence interval
Parameters
Male
(n=132)
Female
(n=123)
90% CI for lower
limit
90% CI for upper
limit
WBC (X 109/I)
4.0 – 9.6
4.2 – 11.9
M = 3.7 - 4.6
F =3.8 - 4.8
M = 8.9 - 9.7
F = 11.0 - 12.3
RBC (X1012/l)
4.50 – 5.90
3.95 – 5.22
M = 4.54 - 4.59
F = 3.92 - 4.06
M = 5.73 - 6.11
F = 5.03 - 5.34
HB (g/l )
129.3 – 171.7
119.1 – 146.0
M = 129.0 - 136.0
F = 114.0 - 121.0
M = 168.0 - 175.0
F = 145.0 - 151.0
HCT (%)
0.39 – 0.50
0.36 – 0.43
M = 0.38 - 0.40
F = 0.35 - 0.37
M = 0.49 - 0.51
F = 0.43 - 0.44
MCV (fl)
80 – 94
80 – 96
M = 79 – 81
F = 80 - 81
M = 93 - 95
F = 94 - 96
MCH (pg)
26.5 – 32.0
26.5 – 31.4
M = 26.5 - 27.2
F = 26.2 - 26.8
M = 31.3 - 32.6
F = 31.0 - 32.5
MCHC (g/dl)
322 – 354
309 – 345
M = 317 -323
F = 305 - 314
M = 350 - 356
F = 344 - 349
PLT (X109/l)
171 -340
184 – 386
M =162 -189
F = 162 - 216
M= 327- 355
F = 375- 400
RDW (CV%)
11.9 – 14.9
11.9 – 15.0
M = 11.8 - 12.4
F = 11.7 - 12.6
M = 14.7 - 15.1
F = 14.9 - 15.1
RETIC (%)
0.54 – 1.61
0.53 – 1.75
M = 0.50 - 0.66
F = 0.50 - 0.60
M = 1.51 - 1.84
F = 1.67 - 1.78
NEUTROPHIL (%)
37.12 – 68.17
41.65 – 71.78
M = 32.60 - 40.40
F = 38.90 - 44.90
M = 65.60 - 76.90
F = 67.20 - 72.90
LYMPHOCYTE(%
)
21.56 – 52.35
20.30 – 45.39
M = 16.40 - 23.00
F = 18.00 - 22.50
M = 48.10 - 55.60
F = 44.50 - 48.80
MONOCYTE (%)
4.99 – 11.56
4.01 – 10.79
M = 4.30 - 5.50
F = 3.60 - 4.50
M = 11.20 - 12.20
F = 9.80 - 11.00
EOSINOPHIL (%)
0.73 – 6.20
0.51 – 6.40
M = 0.30 - 1.10
F = 0.40 - 0.70
M = 5.70 - 7.00
F = 5.90 - 7.10
BASOPHIL (%)
0.13 – 1.20
0.10 -0.10
M = 0.00 - 0.20
F = 0.10 - 0.10
M =1.00 - 1.20
F = 0.80 - 0.90
IRON (µmol/l)
8.03 – 30.40
6.74 – 25.90
M = 7.70 - 8.70
F = 5.40 - 7.80
M = 27.80 - 31.50
F = 21.70 - 26.70
FERRITIN (µg/l)
16 – 212
15 – 99
M = 13 - 19
F = 12 - 16
M = 190 - 235
F = 88 - 100
STFR (mg/l)
0.91 – 2.81
0.80 – 2.17
M = 0.89 - 1.06
F = 0.76 - 0.83
M = 2.32 - 2.95
F = 2.12 - 2.23
TRF (g/l)
1.85 – 3.18
2.01 – 3.38
M = 1.32 - 2.03
F = 1.91 - 2.11
M = 3.13 - 3.27
F = 3.28 - 3.56
Table 2: Comparison of reference interval of adult haematological value obtained in this study against
previous adult Malaysian study by USM and UK population.
Parameter
Gender
UK study
USM study
Our Study
HB (g/dl)
M
F
13.7 – 17.2
12.0 – 15.2
12.01 – 16.53
9.8 – 13.85
12.9 – 17.1
11.9 – 14.6
RBC (x1012/1)
M
F
4.5 – 5.6
3.9 – 5.1
4.18 – 6.06
3.52 – 5.16
4.50 – 5.90
3.95 – 5.22
HCT %
M
F
0.40 – 0.50
0.37 – 0.46
0.37 – 0.49
0.31 – 0.42
0.39 – 0.50
0.36 – 0.43
MCV (fl)
M
F
83 – 98
85 – 98
78.9 – 95.74
77.49 – 94.49
80 – 94
80 – 95
MCH (pg)
M
F
28 – 33
28 – 33
25.38 – 31.1
24.75 – 31.23
26.5 – 31.4
26.5 – 32.0
MCHC (g/dl)
M
F
32 – 36
32 – 35
30.58 – 34.82
29.43 – 34.35
32.0 – 35.4
30.0 – 34.5
RDW (CV %)
M
F
11.6 – 14.1
12.0 – 14.7
11.2 – 15.1
11.3 – 15.0
11.9 – 14.9
11.9 – 15.0
PLT (x109/l)
M
F
140 – 320
180 – 380
166.60 – 376.05
157.88 – 410.33
171 – 340
184 – 386
Ferritin
M
F
11 – 215
5 – 119
55.7 – 173.48
14.45 – 87.75
16 – 212
15 – 99
3.6 – 9.2
M = 3.78 – 9.7
F = 3.37 – 10.09
M = 4.0 – 9.6
F = 4.2 – 11.9
WBC (x109/l)
Discussion
The primary objective of this study was to establish the reference intervals
for routine haematological parameters and two surrogate markers for iron status
which are soluble serum transferrin receptor and serum transferrin. All samples
collected were subjected to serum ferritin analysis. To exclude iron deficient
individuals, a cut off value of serum ferritin < 15 ug/L was used whereas MCH of <
25 pg was used to exclude undiagnosed haemoglobinopathies.
The reference interval and the 90 % confidence interval for red cell
parameters (Table 1) such as RBC, Hct, Hb, MCH and MCHC are higher for
males than for females. This difference is attributed to the influence of androgen
hormone on erythropoiesis and menstrual loss in females. The difference in
reference intervals for Hb, RBC, Hct, MCH, MCHC and red cell distribution width
(RDW) for both genders were statistically significant whereas MCV and
reticulocytes showed no significant difference.
Our results for red cell parameters differed with that reported in a previous
study for Malaysian donors by University Sains Malaysia (USM). The Hb, platelet
count, MCV, MCH, MCHC, RBC, Hct are higher in our study, similar to the results
of UK population (Table 2). This can be attributed to the fact that iron deficient
donors may have been included in the USM study. In comparison to the current
reporting range in use, the values obtained are similar, of note the reference
interval obtained for RBC is higher for our population.
The white cell count (WBC) was noted higher in females than in males.
The neutrophil and lymphocyte values also reflect higher values in the female
population. Similar findings were noted in other population studies and it is in
agreement that the total leucocyte and the neutrophil counts are slightly higher in
females. Our study showed different reference intervals for WBC, neutrophil,
lymphocyte, monocyte, eosinophil and basophil for males and females which was
not the case with the previous USM and UK study.
The platelet value was higher for females than in males. The reference
interval was and the difference was statistically significant. Similar findings were
also noted in other similar studies in African, Indian, Pakistani and UK populations.
The reasons for this difference is are still unclear.
Serum transferrin and serum soluble transferrin receptor levels haves
been advocated as more sensitive and less variable indicesex of iron studies. We
believe that the measurement of the above parameters along with the conventional
markers such as serum iron and ferritin will aid the clinician to reliably diagnose
iron deficiency in the presence of chronic illnesses. Our study findings shows that
the reference interval for serum transferrin and serum soluble transferrin receptor
is not significantly different between males and females for both genders. The
established reference interval established for the soluble serum transferrin
receptor value shows a higher cut off value than the manufacturers’.
Our study validates the principle that one should use method specific
reference intervals that are established in one own’s laboratory. We want to adopt
the established reference interval into the current reporting scheme because the
diversity of the population in this study is low and it reflects the local population our
laboratory caters to.
References
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