C om parison of red cell distribution w idth and a red cell
discrim inant function incorporating volum e dispersion for
distinguishing iron deficiency from beta thalassemia trait in
patients w ith m icrocytosis
Department of Clinical Medicine and Hemocentro, Department of
Clinical Pathology, Faculty of Medical Sciences, University of Campinas - Campinas, Brazil
T h e r e d c e ll d is tr ib u tio n w id th ( R O W ) , a n d a n o th e r r e d c e ll d is c r im in a n t fu n c tio n in c o r p o r a tin g R O W ( M C V 2 x R O W /H g b x 1 0 0 ) w e r e d e te r m in e d in a g r o u p o f 3 0 p a tie n ts w ith ir o n d e fic ie n c y a n e m ia , 3 0 p a tie n ts w ith b e ta th a la s s e m ia tr a it, a n d 3 0 n o r m a l s u b je c ts . B o th R O W a n d ( M C V 2 x R O W /H g b x 1 0 0 ) m e a n v a lu e s w e r e s ig n ific a n tly h ig h e r in ir o n d e fic ie n c y a n e m ia th a n in b e ta th a la s s e m ia tr a it ( p < 0 .0 0 1 ) . T a k in g R O W e q u a l o r a b o v e 2 1 .0 p e r c e n t a m o n g m ic r o c y tic a n e m ia p a tie n ts , w e id e n tifie d c o r r e c tly 9 0 .0 p e r c e n t o f p a -tie n ts w ith ir o n d e fic ie n c y a n e m ia . T h e s e n s itiv ity a n d s p e c ific ity o f th e te s t w e r e 9 0 .0 p e r c e n t ( IC 9 5 p e r c e n t: 0 .7 5 - 0 .9 6 ) a n d 7 7 .0 p e r c e n t ( IC 9 5 p e r c e n t: 0 .6 0 - 0 .8 8 ) , r e s p e c tiv e ly . R O W v a lu e s b e lo w 2 1 .0 p e r c e n t id e n tifie d c o r r e c tly 7 7 .0 p e r c e n t o f b e ta th a la s s e m ia , tr a it w ith a s e n s itiv ity a n d a s p e c ific ity o f 7 7 .0 p e r c e n t ( IC 9 5 p e r c e n t: 0 .6 0 - 0 .8 8 ) a n d 9 0 .0 p e r c e n t ( IC 9 5 p e r c e n t: 0 .7 5 - 0 .9 6 ) ,
r e s p e c tiv e ly . T a k in g v a lu e s o f ( M C V 2 x R O W /H g b x 1 0 0 ) a b o v e a n d b e lo w 8 0 .0 p e r c e n t a s in d ic a tiv e o f ir o n d e fic ie n c y a n d b e ta th a la s s e m ia tr a it, r e s p e c tiv e ly , w e id e n tifie d c o r r e c tly 9 7 .0 p e r c e n t o f th o s e p a tie n ts in e a c h g r o u p . B o th s e n s itiv ity a n d s p e c ific ity w e r e 9 7 .0 p e r c e n t ( IC 9 5 p e r c e n t: 0 .8 4 - 0 .9 9 ) . T h e s e r e s u lts in d ic a te d th a t th e r e d c e ll d is c r im in a n t fu n c tio n in c o r p o r a tin g v o lu m e d is p e r -s io n ( M C V 2 x R O W /H g b x 1 0 0 ) i-s a h ig h ly -s e n -s itiv e a n d -s p e c ific m e th o d in th e in itia l -s c r e e n in g o f p a tie n t-s w ith m ic r o c y tic a n e m ia a n d is b e tte r th a n R O W in d iffe r e n tia tin g ir o n d e fic ie n c y a n e m ia fr o m b e ta th a la s s e m ia tr a it.
U N IT E R M S : M ic r o c y tic a n e m ia . R e d c e ll d is c r im in a n t fu n c tio n .
IN T R O D U C T IO N
I
it is p ro b a b lyro nd e fic ie n c yth e m o st c o m m o nis w id e sp re a d th ro u g h o u tc h ro n ic o rg a n ic m a la d yth e w o rld a n d o f h u m a n k in d . O n th e o th e r h a n d , in m a n y p a rts o fA d r e s s fo r c o r r e s p o n d e n c e : S ara Teresinha O llala S aad H em ocentro/U N IC A M P C aixa P ostal 6198
C am pinas/S P - B rasil- C E P 13081-970
th e w o rld , th e fre q u e n c y o f b e ta th a la sse m ia is se c o n d o n ly
to th a t o f iro n d e fic ie n c y a s a c a u se o f h y p o c h ro m ic m ic ro c y tic a n e m ia . A lth o u g h se v e re fo rm s o f b e ta
th a la sse m ia , in g e n e ra l, a re e a sily re c o g n iz e d , m ild e r fo rm s
m a y b e m isd ia g n o se d a n d tre a te d a s iro n d e fic ie n c y .,.2
S e v e ra l sc re e n in g m e th o d s, o b ta in e d fro m th e g e n e ra tio n
o f re d b lo o d c e ll in d ic e s b y e le c tro n ic c o u n te rs, h a v e b e e n
p ro p o se d to d iffe re n tia te iro n d e fic ie n c y fro m b e ta th a la sse m ia tra it.3-x T h e u se fu ln e ss o f re d b lo o d c e ll
d istrib u tio n w id th (R D W ), a n in d e x o f re d b lo o d c e ll siz e h e te ro g e n e ity , in th e c la ssific a tio n a n d w o rk u p o f
m ic ro c y tic a n e m ia s h a s b e e n d o c u m e n te d .3 .lJ -'2
L IM A , C .S .P .; R E IS , A .R .C .; G R O n O , H .Z .w . e t a l. - C o m p a r is o n o f r e d c e ll d is tr ib u tio n w id th a n d a r e d c e ll d is c r im in a n t fu n c tio n
1 8
R E S U L T S
F ig u re 1 - D is trib u tio n o f th e v a lu e s o f R O W in 3 0 p a tie n ts w ith iro n d e fic ie n c y a n e m ia , 3 0 p a tie n ts w ith b e ta th a la s s e m ia tra it a n d 3 0 c o n tro ls .
C o n tro ls Iro n T h a la s s e m ia
D e fic ie n c y T ra it 1 4
36
34
32
30
;g 28
.
~
..
~ 26
..
..
0. 1 .
-a :24
.
.).... .l.
.l.
22 .l.
+
.
A ••A"l
20
•
-."'1 •._.~ .
A"
1 6
T h e d is trib u tio n s o f v a lu e s o f R D W a n d (M C y 2 x
R D W /H g b x 1 0 0 ) in 3 0 p a tie n ts w ith iro n d e fic ie n c y
a n e m ia , 3 0 p a tie n ts w ith b e ta th a la s s e m ia tra it a n d 3 0
c o n tro ls a re s h o w n in F ig u re I a n d 2 .
T h e m e a n v a lu e s o f R D W in iro n d e fic ie n c y w e re
s ig n ific a n tly h ig h e r th a n in b e ta th a la s s e m ia tra it (2 4 .3 :t
4 .0 v s 2 0 .0 :t 1 .3 ; p < O .O OI) .T h e m e a n R D W c o n tro ls w a s
lo w e r (1 5 .7 :t 0 .7 ) th a n th e v a lu e s o b s e rv e d in iro n
d e fic ie n c y a n e m ia a n d b e ta th a la s s e m ia tra it (p < O .O OI) .
R D W a b o v e 2 4 .0 p e rc e n t w a s o b s e rv e d o n ly in iro n
d e fic ie n c y , c o m p ris in g 4 3 .0 p e rc e n t o f th is p o p u la tio n . O n
th e o th e r h a n d , v a lu e s b e lo w 2 0 .0 p e rc e n t w e re o b s e rv e d
o n ly in b e ta th a la s s e m ia tra it, c o m p ris in g 6 0 .0 p e rc e n t o f
th e s e p a tie n ts .
T h e m e a n v a lu e s o f th e re d c e ll d is c rim in a n t fu n c tio n
in c o rp o ra tin g v o lu m e d is p e rs io n (M C y2
x R D W /H g b x
1 0 0 ) w e re s ig n ific a n tly h ig h e r in iro n d e fic ie n c y th a n in
b e ta th a la s s e m ia tra it (1 0 8 .0 :t 1 7 .3 a n d 6 8 .0 :t 5 .7 ,
re s p e c tiv e ly ; p < O .O OI )o r th a n in n o rm a l s u b je c ts (8 6 .5 :t
9 .I ;p < 0 .0 0 I ) .T h is in d e x w a s s ig n ific a n tly lo w e r in b e ta
W e s tu d ie d 6 0 p a tie n ts w ith m ild m ic ro c y tic a n e m ia
(3 0 w ith iro n d e fic ie n c y a n e m ia a n d 3 0 w ith b e ta
th a la s s e m ia tra it), s e e n a t th e U n iv e rs ity H o s p ita l o f
C a m p in a s . T h e p a tie n ts p re s e n te d h e m o g lo b in (H g b ) le v e ls
a b o v e 8 g /d L : b e lo w 1 2 g /d L fo r fe m a le s ; a b o v e 8 g /d L a n d
b e lo w 1 4 g /d L fo r m a le s a n d M C V < 8 0 tl.T h e s e t c o n s is te d
o f 3 0 p a tie n ts w ith iro n d e fic ie n c y a n e m ia a n d 3 0 p a tie n ts
w ith b e ta th a la s s e m ia tra it. T h irty b lo o d d o n o rs w ith
n o rm a l H g b le v e ls (1 2 -1 6 g /d L fo r fe m a le s , 1 4 -1 8 g /d L
fo r m a le s ) a n d M C V 8 0 -9 4 fl w e re ta k in g a s c o n tro ls .
T h e d ia g n o s is o f iro n d e fic ie n c y w a s b a s e d o n th e
d e te rm in a tio n o f s e ru m iro n , s e ru m to ta l iro n b in d in g
c a p a c ity , a n d s e ru m fe rritin . S e ru m iro n a n d s e ru m to ta l
iro n b in d in g c a p a c ity w e re d e te rm in e d b y c o lo rim e tric
m e th o d (L a b te s t d ia g n 6 s tic a ). S e ru m fe rritin w a s
d e te rm in e d u s in g e n z y m e im u n o a s s a y (S tra tu s fe rritin
flu o ro m e tric e n z y m e im m u n o a s s a y - B a x te r D ia g n o s tic s
In c ., U S A ). T h e d ia g n o s is o f iro n d e fic ie n c y w a s
e s ta b lis h e d if s e ru m iro n w a s b e lo w 3 7 ~ g /d L fo r fe m a le s ,
a n d b e lo w 4 5 ~ g /d L fo r m a le s . S e ru m to ta l iro n b in d in g
c a p a c ity w a s a b o v e 3 9 0 ~ g /d L , a n d s e ru m fe rritin w a s
b e lo w 1 0 n g /d L fo r fe m a le s a n d b e lo w 3 0 n g /d L fo r m a le s .
H e m o g lo b in e le tro p h o re s is w a s p e rfo rm e d o n c e llu lo s e
a c e ta te m e m b ra n e , p H 8 .6 a n d H g b A 2 w a s e lu te d fo r
q u a n tita tio n .'3 T h e d ia g n o s is o f b e ta th a la s s e m ia tra it w a s
m a d e if H b A 2 v a lu e w a s a b o v e 3 .4 p e rc e n t. R D W a n d
re d c e ll d is c rim in a n t fu n c tio n (M C Y 2 x R D W /H g b x 1 0 0 )
w e re o b ta in e d fro m b lo o d c o u n ts c a rrie d o u t u s in g a n
a u to m a te d in s tru m e n t (C e ll-D y n , M o d e l 1 6 0 0 C S ).
O p tim a l d ia g n o s tic le v e ls fo r e a c h s y s te m w e re
e s ta b lis h e d o n th e b a s is o f s e n s itiv ity a n d s p e c ific ity o f
v a lu e s o b ta in e d fro m v a rio u s d e c is io n le v e ls , e m p iric a lly
d e te rm in e d . T h e s ig n ific a n c e s o f d iffe re n c e s b e tw e e n
g ro u p s w e re d e te rm in e d b y th e M a n n W h itn e y te s t.1 4T h e
c o n fid e n c e in te rv a ls w e re d e te rm in e d a c c o rd in g to
S im o n .ls
M A T E R IA L S A N D M E T H O D S
A n o th e r re d c e ll d is c rim in a n t fu n c tio n (M C Y 2 x
R D W /H g b x 1 0 0 ) w a s d e s c rib e d b y G re e n a n d K in g
(1 9 8 9 ). A c c o rd in g to th e s e a u th o rs , th e u s e o f th is
p a ra m e te r re s u lts in e n h a n c e d a c c u ra c y in d is tin g u is h in g
iro n d e fic ie n c y a n e m ia fro m b e ta th a la s s e m ia tra it. T h e
p u rp o s e o f th is s tu d y w a s to a s s e s s th e c lin ic a l u tility o f
e a c h o n e o f th e s e a p p ro a c h e s in d iffe re n tia tin g th e s e ty p e s
o f a n e m ia . D e te rm in a tio n s o f s e ru m iro n , tra n s fe rrin ,
fe rritin a n d h e m o g lo b in e le tro p h o re s is w e re u s e d to
d e te rm in e th e d ia g n o s is o f th e s e a n e m ia s .
Figure2 - Distribution of the values of (M CV2 x RDW /Hgb x 100)
in 30 patients with iron deficiency anem ia, 30 patients with beta thalassem ia trait and 30 controls.
th a la sse m ia tra it th a n in n o rm a l su b je c ts (p < O .O O I). W h e n m ic ro c y tic a n e m ia w a s c o n sid e re d , v a lu e s a b o v e 8 5 .0 p e rc e n t w e re o b se rv e d o n ly in iro n d e fic ie n c y a n e m ia , c o m p risin g 9 0 .0 p e rc e n t o f th is p o p u la tio n a n d v a lu e s b e lo w 7 5 .0 p e rc e n t w e re o b se rv e d o n ly in b e ta th a la sse m ia tra it, in c lu d in g 8 3 .0 p e rc e n t o f th is p o p u la tio n . T h e se re su lts a re re p re se n te d in F ig u re 3 .
O n th e b a sis o f th e m a x im u m se n sitiv ity a n d sp e c ific ity w e c h o se , a s d isc rim in a n t, th e v a lu e s o f 2 1 .0 p e rc e n t fo r R D W a n d 8 0 .0 p e rc e n t fo r (M C y 2 x R D W / H g b x 1 0 0 ). T h e p ro p o rtio n s o f c o rre c tly id e n tifie d p a tie n ts a c c o rd in g to th e se d e c isio n le v e ls a re sh o w n in T a b le I. A m o n g m ic ro c y tic a n e m ia p a tie n ts, R D W v a lu e s e q u a l o r a b o v e 2 1 .0 p e rc e n t w e re in d ic a tiv e o f iro n d e fic ie n c y w ith th e se n sitiv ity o f9 0 .0 p e rc e n t (IC 9 5 p e rc e n t: 0 .7 5 - 0 .9 6 ) a n d sp e c ific ity o f7 7 .0 p e rc e n t (IC 9 5 p e rc e n t: 0 .6 0 - 0 .8 8 ). R D W v a lu e s b e lo w 2 1 .0 p e rc e n t w e re in d ic a tiv e o f b e ta th a la sse m ia tra it w ith th e se n sitiv ity o f 7 7 .0 p e rc e n t (IC 9 5 p e rc e n t: 0 .6 0 - 0 .8 8 ) a n d sp e c ific ity o f 9 0 .0 p e rc e n t (IC 9 5 p e rc e n t: 0 .7 5 - 0 .9 6 ). (M C y 2 x R D W /H g b x 1 0 0 ) e q u a l o r a b o v e 8 0 .0 p e rc e n t w e re in d ic a tiv e o f iro n d e fic ie n c y a n e m ia , w h ile v a lu e s b e lo w 8 0 .0 p e rc e n t w e re in d ic a tiv e o f b e ta th a la sse m ia tra it a n d b o th se n sitiv ity a n d sp e c ific ity w e re 9 7 .0 p e rc e n t (IC 9 5 p e rc e n t: 0 .8 4 - 0 .9 9 ).
160
155
150
0 145 0
140
x
135
. 0
I 130
~ 125
0
120
a : x 115
'>
() 110~ 105
100
95
90
85
80
75
70
65
60
55
~
,
,
Iron Thalassem ia
Deficiency Trait Controls
DISCUSSION
M ic ro c y to sis is a c la ssic a l la b o ra to ry fe a tu re o f th e d iso rd e rs o f h e m o g lo b in sy n th e sis, su c h a s iro n d e fic ie n c y a n d b e ta th a la sse m ia tra it. B e c a u se o f th e h ig h fre q u e n c y o f th e se a b n o rm a litie s in se v e ra l p o p u la tio n s, m a n y sc re e n in g m e th o d s h a v e b e e n d e sc rib e d a s to d iffe re n tia te b o th d iso rd e rs.2 -6
.16 M o st o f th e m a re b a se d o n th e fa c t
th a t, in iro n d e fic ie n c y a n e m ia , th e a n iso c y to sis is m o re p re d o m in e n t th a n in b e ta th a la sse m ia tra it. M ic ro c y to sis is u su a lly m o re p re d o m in e n t in b e ta th a la sse m ia tra it th a n in iro n d e fic ie n c y a n d it is p ro p o rtio n a l to th e d e g re e o f a n e m ia in iro n d e fic ie n c y .
In th is stu d y , th e m e a n v a lu e s o f R D W o b se rv e d in iro n d e fic ie n c y w e re sig n ific a n tly h ig h e r th a n in b e ta th a la sse m ia tra it. T h is re su lt c a n b e e x p la in e d b y th e fa c t th a t a n iso c y to sis fo u n d in iro n d e fic ie n c y a n e m ia is d u e to th e c o e x iste n c e , in p e rip h e ra l b lo o d , o f re d c e lls p ro d u c e d in th e b o n e m a rro w d u rin g p ro g re ssiv e d e g re e s o f iro n d e fic ie n c y , g iv in g rise to a m ix e d p o p u la tio n o f n o rm o c y tic a n d in c re a sin g ly m ic ro c y tic c e lls. In b e ta th a la sse m ia tra it, th e re is n o flu c tu a tio n s in th e u n d e rly in g d iso rd e r a n d th e b o n e m a rro w p ro d u c e s a u n ifo rm p o p u la tio n o f m ic ro c y tic c e lls.3 ,().'J,'2 .'7
B a se d o n th e m a jo r v a lu e s o f b o th se n sitiv ity a n d sp e c ific ity , w e c h o se d iffe re n t d e c isio n le v e ls o f R D W , a n d o f th e re d c e ll d isc rim in a n t fu n c tio n in c o rp o ra tin g v o lu m e d isp e rsio n fo r d istin g u ish in g iro n d e fic ie n c y fro m b e ta th a la sse m ia tra it. T h u s, a m o n g m ic ro c y tic a n e m ia p a tie n ts, v a lu e s o f R D W a b o v e 2 4 .0 p e rc e n t a n d b e lo w 2 0 .0 p e rc e n t w e re o b se rv e d o n ly in iro n d e fic ie n c y a n e m ia a n d b e ta th a la sse m ia tra it, re sp e c tiv e ly , c o m p risin g a b o u t a n h a lf o f e a c h p o p u la tio n . H o w e v e r, 9 0 .0 p e rc e n t o f p a tie n ts w ith iro n d e fic ie n c y a n e m ia a n d 7 7 .0 p e rc e n t o f b e ta th a la sse m ia m in o r p a tie n ts w e re c o rre c tly id e n tifie d u sin g R D W v a lu e s a b o v e o r b e lo w 2 1 .0 p e rc e n t, re sp e c tiv e ly . T h u s, th is d isc rim in a n t fu n c tio n se e m to b e a se n sitiv e a n d sp e c ific m e th o d to id e n tify iro n d e fic ie n c y a m o n g m ic ro c y tic a n e m ia p a tie n ts, a lth o u g h it w a s n o t a g o o d in d e x fo r th e id e n tific a tio n o f b e ta th a la sse m ia tra it. T h u s a c le a r d istin c tio n b e tw e e n th e se d iso rd e rs c a n n o t b e m a d e b a se d o n R D W a lo n e .
O n th e o th e r h a n d , th e m e a n v a lu e s o f th e G re e n a n d K in g in d e x w e re sig n ific a n tly h ig h e r in iro n d e fic ie n c y a n e m ia th a n in b e ta th a la sse m ia tra it. A m o n g su b je c ts w ith m ic ro c y to sis, v a lu e s o f th is d isc rim a n t fu n c tio n a b o v e 8 5 .0 p e rc e n t a n d b e lo w 7 5 .0 p e rc e n t w e re o b se rv e d o n ly in iro n d e fic ie n c y a n d b e ta th a la sse m ia tra it, re sp e c tiv e ly , c o m p o sin g 9 0 .0 p e rc e n t a n d 8 3 .0 p e rc e n t o f e a c h p o p u la tio n . T h e G re e n a n d K in g in d e x a b o v e o r b e lo w 8 0 .0 p e rc e n t id e n tifie d c o rre c tly 9 7 .0 p e rc e n t o f p a tie n ts
LIM A, C.S,P.; REIS, A.R.C.; G RO nO , H.ZW . et al. • Com parison of red cell
distribution width and a red cell discrim inant function
77
9 7 9 0
97 <21
<80
Decision level Correctly identified
Discriminant cases (%)
function ID THAL ID
THAL
(n=30) (n=30)
RDW ~21
MCV2 RDW ~80
--- x ---Hgb 100
Table 1
Proportion of correctly-identified cases by the discriminant functions in iron deficiency anemia patients (10) and beta thalassemia trait
patients (THAL)
100
80
~ 60
0
40
20
19 20 21 22 23 24 25
R O W
II Sensibility -A- SpecificityI
100
80
4 0
?ft. 6 0
T h a n k s is e x p re s s e d to C a rm e n L u c ia R o d rig u e s
A rru d a a n d S a n d ra S o u s a A n d ra d e fo r te c h n ic a l a s s is te n c e .
ACKNOWLEDGMENTS
u s e d th e C e ll-D y n , m o d e l 1 6 0 0 C S , w h ile G re e n a n d K in g
( 1 9 8 9 ) u s e d th e C o u lte r S+IV , w h ic h m a y re s u lt in s e v e ra l
d iffe re n c e s in c lu d in g : th e p rin c ip le o fth e d e te c t\o n s y s te n l
u s e d in th e s e in s tru m e n ts ;th e s e le c tio n o r tru n c a tio n o f
th e e v e n ts fo r re d c e lls a n a ly s is ; a n d c a lib ra tio n fa c to rs .
M o re o v e r, th e m e th o d s u s e d fo r d e te rm in in g th e d e c is io n
le v e l w e re d iffe re n t; in th is s tu d y w e u s e d th e m a jo r v a lu e s
o f s e n s ib ility a n d s p e c ific ity , w h ile in G re e n a n d K in g
( 1 9 8 9 ) s tu d y th e d e c is io n le v e l w a s d e te rm in e d e m p iric a lly .
T h u s , th e re s u lts p re s e n te d in th is s tu d y in d ic a te d
th a t th e re d c e ll d is c rim in a n t fu n c tio n s R D W a n d (M C y 2
x R D W /H g b x 1 0 0 ) m ig h t b e u s e fu l in th e in itia l s c re e n in g
o f s u b je c ts w ith m ic ro c y to s is fo r d is tin g u is h in g iro n
d e fic ie n c y a n d b e ta -th a la s s e m ia tra it, a n d m a y s u g g e s t
w h ic h a d d itio n a l te s ts s h o u ld b e d o n e to c o n firm th e c o rre c t
d ia g n o s is .
8 4
78 80 82
MCV2 x ROW
IHbx 100
20 -l---,
7 6
Figure 3 - Proportional of correctly diagnosed iron deficiency anemia patients according different decision levels for the discriminant function: ROW (A) and MCV2 x ROW/Hgb x 100 (8).
w ith iro n d e fic ie n c y a n e m ia , a n d 9 7 .0 p e rc e n t o f b e ta
th a la s s e m ia tra it p a tie n ts , re s p e c tiv e ly . T h u s , th is
d is c rim in a n t fu n c tio n a p p a re n tly is a v e ry s e n s itiv e a n d
s p e c ific m e th o d in th e in itia l s c re e n in g fo r p a tie n ts w ith
m ic ro c y tic a n e m ia . S im ila r re s u lts w e re o b ta in e d b y G re e n
a n d K in g ( 1 9 8 9 ) , a lth o u g h th e s e a u th o rs u s e d a d iffe re n t
d e c is io n le v e l to d is tin g u is h b o th d is o rd e rs . T h e d iffe re n c e
b e tw e e n th e d e c is io n le v e ls c a n b e e x p la in e d b y s e v e ra l
fa c to rs , in c lu d in g th e ty p e s o f e le tro n ic c o u n te rs u s e d fo r
th e g e n e ra tio n o f re d b lo o d c e lls in d e x . In th is s tu d y w e
RESUMO
A fu n y a o d is c r im in a n te b a s e a d a n a d is tr ib u iy a o d o ta m a n h o d o s e r itr o c ito s ( R O W ) e o u tr a fu n y a o d is c r im in a n te in c o r p o r a n d o
o R O W ( M C V 2XR O W /H g b x 1 0 0 ) fo r a m d e te r m in a d a s e m u m g r u p o d e 3 0 p a c ie n te s c o m a n e m ia fe r r o p r iv a , 3 0 p a c ie n te s c o m b e ta ta la s s e m ia m e n o r e 3 0 in d iv fd u o s n o r m a is . O s v a lo r e s m e d io s d o R O W e d o ( M C V 2 x R O W / H g b x 1 0 0 ) fo r a m
s ig n ific a tiv a m e n te m a io r e s e m p a c ie n te s c o m a n e m ia fe r r o p r iv a q u a n d o c o m p a r a d o s a o s o b tid o s e m p a c ie n te s c o m b e ta
talassemia m e n o r ( p < 0 .0 0 1 ) . C o n s id e r a n d o o s v a lo r e s d e R O W ig u a is o u s u p e r io r e s a 2 1 .0 % e n tr e o s p a c ie n te s c o m a n e m ia m ic r o c ftic a , n o s id e n tific a m o s c o r r e ta m e n te 9 0 % d o s p a c ie n te s c o m a n e m ia fe r r o p r iv a , s e n d o q u e a s e n s ib ilid a d e e a
e s p e c ific id a d e d o te s te fo r a m 9 0 .0 % ( IC 9 5 % : 0 .7 5 - 0 .9 6 ) e 7 7 .0 % ( IC 9 5 % : 0 .6 0 - 0 .8 8 ) , r e s p e c tiv a m e n te . V a lo r e s d e R O W m e n o r e s d o q u e 2 1 .0 % id e n tific a r a m c o r r e ta m e n te 7 7 .0 % d o s p a c ie n te s c o m b e ta ta la s s e m ia m e n o r , c o m s e n s ib ilid a d e e
e s p e c ific id a d e d e 7 7 .0 % ( IC 9 5 % : 0 .6 0 - 0 .8 8 ) e 9 0 .0 % ( IC 9 5 % : 0 .7 5 - 0 .9 6 ) , r e s p e c tiv a m e n te . C o n s id e r a n d o v a lo r e s d e ( M C V 2 x R O W /H g b x 1 0 0 ) m a io r e s e m e n o r e s d o q u e 8 0 .0 % c o m o in d ic a tiv o s d e a n e m ia fe r r o p r iv a e b e ta ta la s s e m ia m e n o r ,
r e s p e c tiv a m e n te , n o s id e n tific a m o s c o r r e ta m e n te 9 7 .0 % d o s p a c ie n te s d e c a d a g r u p o , c o m s e n s ib ilid a d e e e s p e c ific id a d e d e 9 7 .0 ( IC 9 5 % : 0 .8 4 - 0 .9 9 ) . E s te s r e s u lta d o s in d ic a r a m q u e a fu n y a o d is c r im in a n te ( M C V 2 x R O W /H g b x 1 0 0 ) e u m m e to d o
a lta m e n te s e n s fv e l e e s p e c ffic o p a r a a tr ia g e m in ic ia l d e p a c ie n te s c o m a n e m ia m ic r o c ftic a e e s u p e r io r a o R O W p a r a a
d ife r e n c ia y a o d e p a c ie n te s c o m a n e m ia fe r r o p r iv a d a q u e le s c o m b e ta ta la s s e m ia m e n o r .
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