Proposal of a score combining red blood cell indices for early differentiation of beta‐thalassemia minor from iron deficiency anemia

Figures & data

Table 1. Hematological data of the two patient groups

	IDA (mean value±SD)	BTm (mean value±SD)	Significance
Hb (g/dl)	9·5±2·0	11·2±1·3	P<0·01
RBC (1012/l)	4·4±0·8	5·7±0·7	P<0·01
MCV (fl)	70·8±8·4	61·6±4·6	P<0·01
RDW (%)	17·9±3·2	16·2±1·0	P<0·01
MCH (pg)	21·8±3·8	19·9±1·5	P<0·01
Ferritin (ng/ml)	11·3±9·2	177·7±162·3	P<0·01

Note: IDA, iron deficiency anemia; BTm, beta‐thalassemia minor; SD, standard deviation; Hb, hemoglobin; RBC, red blood count; MCV, mean corpuscular volume; RDW, red blood width; MCH, mean corpuscular haemoglobin. Statistical significances of differences between groups were determined using a Student’s t‐test.

Figure 1. Receiver operative characteristic curves of different RBC indices. (A) 11T: ROC curves of our new score; EF: England and Fraser; GK: Green and King; S: Srivastava; SL: Shine and Lal. (B) 11T: ROC curves of our new score; MI: Mentzer index; RBC: red blood count; RDW: red blood distribution; RDWI: red blood distribution width index. (C) 11T: ROC curves of our new score; E: Ehsani; R: Ricerca; Si: Sirdah.

Table 2. Evaluation of different RBC indices in the differentiation of BTm from iron deficiency

RBC index	AUC (95% CI)	BTm cut‐off publish value	BTm criterion value
11T	0·947 (0·892 to 0·978)		>8
GK	0·958 (0·908 to 0·986)	<72	<62
RDWI	0·952 (0·900 to 0·982)	<220	<201
Si	0·947 (0·892 to 0·978)	<27	<30
EF	0·945 (0·890 to 0·977)	<0	<3·6
MI	0·921 (0·861 to 0·961)	<13	<13·3
E	0·919 (0·858 to 0·960)	<15	<17·3
R	0·911 (0·848 to 0·954)	<4·4	<3·1
RBC	0·909 (0·845 to 0·952)	>5	>5
S	0·865 (0·794 to 0·919)	<3·8	<4
SL	0·770 (0·688 to 0·839)	<1530	<904
RDW	0·664 (0·575 to 0·745)	<14	<17

Note: AUC, area under the curve; CI, confidence interval; GK, Green and King index; RDWI, red blood cell distribution width index; EF, England and Fraser index; Si, Sirdah index; MI, Mentzer index; E, Ehsani index; R, Ricerca index; RBC, red blood cell count; S, Srivastava index; SL, Shine and Lal index; RDW, red blood cell distribution with.

Table 3. The differential values of each discrimination index and the correctly identified number of the patients using these indices in each group and group totals

Index	Sensitivity	Specificity	PPV	NPV	Youden’s Index	Percentage correctly identified patients (%)
11T
IDA	97·50	85·71	91·76	95·45	83·21	93·02
BTm	85·71	97·50	95·45	91·76
GK
IDA	95·00	87·76	92·68	91·49	82·76	92·25
BTm	87·76	95·00	91·49	92·68
RDWI
IDA	95·00	87·76	92·68	91·49	82·76	92·25
BTm	87·76	95·00	91·49	92·68
EF
IDA	86·25	91·84	94·52	80·36	78·09	88·37
BTm	91·84	86·25	80·36	94·52
Si
IDA	83·75	93·88	95·71	77·97	77·63	87·60
BTm	93·88	83·75	77·97	95·71
MI
IDA	82·50	91·84	94·29	76·27	74·34	86·05
BTm	91·84	82·50	76·27	94·29
E
IDA	81·25	93·88	95·59	75·41	75·13	86·05
BTm	93·88	81·25	75·41	95·59
R
IDA	85·00	81·63	88·31	76·92	66·63	83·72
BTm	81·63	85·00	76·92	88·31
RBC
IDA	80·00	87·76	91·43	72·88	67·76	82·95
BTm	87·76	80·00	72·88	91·43
S
IDA	82·50	81·63	88·00	74·07	64·13	82·17
BTm	81·63	82·50	74·07	88·00
SL
IDA	71·25	81·63	86·36	63·49	52·88	75·19
BTm	81·63	71·25	63·49	86·36
RDW
IDA	53·75	87·76	87·76	50·00	41·51	66·67
BTm	87·76	53·75	50·00	87·76

Note: PPV, positive predictive value; NPV, negative predictive value; Youden’s index, sensitivity+specificity–100; GK, Green and King index; RDWI, red blood cell distribution width index; EF, England and Fraser index; Si, Sirdah index; MI, Mentzer index; E, Ehsani; R, Ricerca index; RBC, red blood cell count; S, Srivastava index; SL, Shine and Lal index; RDW, red blood cell distribution width.

Sirdah M, Tarazi I, Al Najjar E, Al Haddad R. Evaluation of the diagnostic reliability of different RBC indices and formulas in the differentiation of the β‐thalassemia minor from iron deficiency in Palestinian population. Int J Lab Hematol 2007;30:324–30.

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