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Table 1 Forty-two discriminant formulae proposed in the literature

From: Multi-criteria decision making to validate performance of RBC-based formulae to screen \(\beta\)-thalassemia trait in heterogeneous haemoglobinopathies

No.

Study

Discriminating formula

Cut-off

Remarks & sample size

1

S & B

\(\frac{MCH}{RBC}\)

<3.8

For thalassemia minor 9 times out of 10, the cut-off value is below, but not applicable in hemodilution and decreased RBC production(SS: 500)

2

E & F

\(MCV-RBC-5 Hb\)

<0

Discriminant function identifies 99% of the cases studied but not applicable in pregnancy (SS: 72)

3

Mentzer

\(\frac{MCV}{RBC}\)

<13

Mentzer classified the highest number of patients correctly (SS: 103)

4

RBC

RBC

>5

The measurement of serum iron concentration and iron-binding capacity are needed for the reliable diagnosis of IDA (SS: 122)

5

S & L

\(\frac{MCV^2 \times MCH}{100}\)

<1530

The false-positives rate was 4.4% (SS:25,302)

6

RDW

RDW

<14

Determination of variation of red cell size by erythrography is a rapid and reliable way to distinguish thalassemia minor (SS:85)

7

Ricerca

\(\frac{RDW}{RBC}\)

<4.4

The sensitivity for the formula is 98% (SS:398)

8

G & K

\(\frac{MCV^2 \times RDW}{100Hb}\)

<65

Use of red cell volume dispersion results in enhanced accuracy for distinguishing IDA from \(\beta\)-TM (SS:102)

9

Das Gupta

1.89RBC - 0.33RDW - 3.28

\(>0\)

Along with the formula and the condition RDW>17.1 recommended for screening (SS:111)

10

MCHD

\(\frac{MCH}{MCV}\)

<0.34

MDHL provided powerful screening for discriminating

11

MDHL

\(\frac{MCH\times RBC}{ MCV}\)

>1.75

between IDA and thalassemia (SS: 96)

12

Jayabose

\(\frac{MCV\times RDW}{RBC}\)

<220

RDW index ensures highest Sens. and Spec. (SS: 102)

13

Huber-Herklotz

\(\frac{MCH\times RDW}{10 RBC}+ RDW\)

\(<20\)

Huber-Herklotz can be used to predict TT with high accuracy (SS:114)

14

Sirdah

\(MCV-RBC-3 Hb\)

<27

Sirdah, G &K or RDWI might be useful in early mass-screening programs (SS: 2196)

15

Kerman- II

\(\frac{MCV\times MCH}{ RBC}\)

<300

Kerman-I formula presented best outcome

16

Kerman- II

\(\frac{MCV\times MCH \times 10}{ RBC\times MCHC}\)

\(<85\)

in screening \(\beta\)-TM (SS:82)

17

Ehsani

\(MCV-10 \times RBC\)

<15

Mentzer and Ehsani formulae presents highest YI (SS:284)

18

Keikhaei

\(\frac{Hb \times RDW \times 100}{RBC^{2} \times MCHC}\)

\(>1.27\)

Keikhaei, G &K, RDW and E &F formulae demonstrates most reliable discrimination in BTT and IDA (SS:823)

19

Wongprachum

\(\frac{MCV\times RDW}{RBC} - 10 Hb\)

<104

The formulae can be used as proxy indicators if none sophisticated laboratory are available (SS:234)

20

Nishad

\(0.615 MCV+0.518 MCH +0.446 RDW\)

<59

Higher Sens is achieved for Ehsani formula, but Spec.is higher for Nishad (SS:326)

21

Sehgal

\(\frac{MCV^{2}}{RBC}\)

<972

Sehgal and Mentzer formulae showed the best combination in predicting \(\beta\)TT (SS: 543)

22

Sargolzaie

\(\begin{array}{c} 125.6 + (44.3 \times RBC)\\ -(20.9 \times Hb)-(2.5 \times MCV)\\ +(20.3 \times MCH)\\ -(12.18 \times MCHC) \end{array}\)

\(<0.5\)

Evaluation of specific information of each region is necessary for discriminating between BTT and IDA (SS:177)

23

Pornprasert

MCHC

<31

Sirdah and Srivastava proved reliable results for discrimination between BTT and IDA (SS: 77)

24

Sirachainan

\(1.5Hb-0.05 MCV\)

>14

Sirachainan demonstrates best AUC score from identifying IDA and thalassemia traits (SS: 345)

25

Bordbar

\(|80-MCV|\times |27-MCH|\)

>44.76

Higher Sens is achieved for Bordbar and S &L, and higher Spec. is achieved for Bordbar and Sirdah (SS: 504)

26

Hameed & Hisham

\(MCH \times HCT \times \frac{RDW}{(RBC \times Hb)^2}\)

<220

Hameed & Hisham was the highest and most reliable in

27

 

\(MCH \times \frac{RDW}{RBC}\)

<67

differentiating BTT from IDA (SS: 600)

28

Matos

\(1.91 \times RBC + 0.44 \times MCHC\)

>23.85

Developed formula provides excellent performance and great diagnostic accuracy (SS: 291)

29

Ravanbakhsh-F1

\(\frac{MCV}{HCT}\)

<2

Best performing discriminating formulae:

30

Ravanbakhsh-F2

\(RDW-3RBC\)

\(<1.5\)

G &K, Keikhaei, RDWI, and E &F are best in terms of YI (SS: 227)

31

Ravanbakhsh-F3

\(MCV\times RDW-100RBC\)

\(<600\)

 

32

Ravanbakhsh-F4

\(\frac{MCV\times Hb}{RDW\times RBC}\)

\(<10\)

 

33

Zaghloul-1 & 2

\(Hb \times HCT + RBC\)

>52.5

E &F and Zaghloul-1 outperforms in discriminating men E &F and RDW outperform for women data set (SS: 249)

34

 

\(Hb \times HCT + RBC - RDW\)

>37.1

 

35

Kandhro-1 & 2

\(\frac{RBC}{HCT} + 0.5 \times RDW\)

<8.2

Mentzer, E &F, G &K, RDWI, Ricerca, and Huber are reliable

36

 

\(\frac{5RDW}{RBC}\)

\(<16.8\)

formulae for ease of use in the general population (SS: 610)

37

Merdin-1 & 2

\(\frac{RDW \times RBC}{MCV}\)

\(>1.27\)

RDWI, Alparslan and Merdin-1 demonstrated

38

 

\(\frac{RDW \times RBC\times Hb}{MCV}\)

\(>14.7\)

highest YI (SS: 40)

  

\(\frac{0.66(MCH-27.0)}{3.9} +0.98\)

  

39

Cruise & Index26

\(MCHC + 0.603RBC\)

\(\ge\)42.63

Index26 outperforms existing discriminating formulae and can

  

\(+ 0.523RDW\)

 

be useful to discriminate between IDA and BTT (SS: 907)

40

 

Combination 26 formulae

\(\ge\) 16

 

41

Janel (11T)

Combination 11 formulae

\(\ge\) 8

11T demonstrates best percentage of correctly identified patients between IDA and BTM (SS: 129)

42

\(SCS_{BTT}\)

\(\begin{array}{c} 0.2815MCV+ 0.2015MCH\\ - 0.2641RBC- 0.1693RDW\\ + 0.0835Hb \end{array}\)

<24.99

MLP and decision tree algorithm can jointly ensure 100% sensitivity (SS: 1076)

  1. Formulae: S &B: [20]; E &F: [21]; Mentzer: [22]; RBC: [23]; S &L: [24]; RDW: [25]; Ricerca: [26]; G & K: [27]; Das Gupta: [28]; MCHD & MDHL: [29]; Jayabose: [30]; Huber-Herklotz: [31]; Kerman-I & II:[32]; Sirdah: [33]; Ehsani: [34]; Keikhaei: [35]; Wongprachum: [36]; Nishad: [37]; Sehgal: [38]; Sargolzie: [39]; Sirachainan: [40]; Pornprasert [41]; Bordbar: [42]; Hameed & Hisham: [43]; Matos: [44]; Ravanbakhsh-F1, F2, F3 & F4:[45]; Zaghloul-1 & 2: [6]; Kandhro-1 & 2: [46]; Merdin-1 & 2: [5]; Cruise & Index26: [4]; Janel (11T): [47]; \(SCS_{BTT}\); [18]; SS: sample size