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Tackling the HRP2 False-Negative Challenge in Malaria Diagnosis

Every year on April 25th, people around the world observe World Malaria Day, aimed at promoting global efforts in malaria prevention and control. However, despite concerted efforts over the past two decades, global malaria incidence remains alarmingly high.


According to the latest data from the World Health Organization, there were an estimated 249 million malaria cases worldwide in 2022, with numbers remaining unchanged from 2021. Particularly concerning is the heavy burden of malaria in the African region, which accounts for 94% of global malaria cases and 95% of malaria deaths.



Early diagnosis and treatment of malaria are crucial to reducing disease transmission and mortality. However, current malaria diagnostic methods face limitations, with one of the most prominent issues being false-negatives due to HRP2 gene deletions. HRP2 is a widely used antigen in rapid diagnostic tests (RDTs) for malaria, but increasing numbers of malaria parasites are showing HRP2 gene deletions, compromising test accuracy.


In addition to HRP2, lactate dehydrogenase (LDH) is another commonly used malaria parasite detection marker. While LDH sensitivity is typically lower than HRP2, its importance is heightened in the absence of HRP2. Therefore, the development of high-sensitivity LDH detection methods is imperative to ensure accurate malaria diagnosis.


In response to this challenge, the World Health Organization has put forward a series of recommendations, including transitioning to LDH-based testing and enhancing detection sensitivity. Furthermore, for malaria RDTs companies, the use of combined HRP2 and LDH detection methods is a worthy consideration.



Fapon's Commitment to Supporting Malaria Diagnostics


Since 2001, Fapon has been committed to researching core raw materials for infectious disease diagnostic reagents. Our malaria raw materials, benchmarked against leading international brands, deliver superior performance and have garnered favorable reviews from global partners.


For malaria-endemic regions without prevalent HRP2 gene deletion, we offer high-performance raw materials to facilitate WHO Prequalification (PQ) for mid-tier IVD reagent manufacturers. In regions with prevalent HRP2 gene deletion, we respond proactively to WHO's directives by developing highly sensitive Pf-PLDH raw materials that comply with WHO standards. Our product line includes various combinations of single and multiple lines to support manufacturers in obtaining WHO-PQ certification.


Pf-PLDH Raw Material Product List

Recommended Pairs

Catalog No.

Source

Clonal No.

Subtype

Blocker

Application

Pair 1

BRCMALS216

CHO

22D5

IgM

HIER-R-040

Coating

BRNMALN201

CHO

25F2

IgM

Conjugating

Pair 2

BRCMALS216

CHO

22D5

IgM

HIER-M-004

Coating

BRCMALS212

Mouse

6F10

IgG2b

Conjugating

Pair 3

BRCMALS213

Mouse

4C6

IgG2a

HIER-M-004

Coating

BRCMALS212

Mouse

6F10

IgG2b

Conjugating


Pf-PLDH Product Performance

Features:

1.  Pf-PLDH Single line: Internal control materials showed positive results LOD:  0.4 ng/mL. Samples from the NIBSC reference material 16/376 showed positive results LOD: 2IU/mL.  Samples from the CDC panel showed positive results LOD: 20 parasites/μL.

2. Raw material products in the form of mixed-line testing are available.

3. Pf-PLDH, Pv-PLDH and Pf-HRPⅡ do not cross react with each other.


More details


Pf-pLDH Single line

Pf-pLDH/HRPII Mixed line

Pf/Pv Combo test

Pf antibody for detection

BRNMALN201

BRNMALN201+BRJMALS109

BRCMALS215+BRJMALS109

Pv antibody for detection

/

/

BRNMALN202

Antibody for capture

BRCMALS215

BRCMALS215+BRCMALS107

BRNMALN201+BRCMALS107

Buffer

Sample buffer

B

B

B/B

NIBSC reference diluent buffer

B

B

B/B

Sensitivity (internal control material)

Pf-LDH 10 ng/mL

4

4

B/7

Pf-LDH 5 ng/mL

5

5

B/8

Pf-LDH 2 ng/mL

6

6

B/B

Pf-LDH 0.4 ng/mL

9

9

B/B

Pf-HRP2 10 ng/mL

B

4

B/4

Pf-HRP2 2 ng/mL

B

7

B/7

Pf-HRP2 0.4 ng/mL

B

9

B/9

Pv-LDH 10 ng/mL

B

B

6/B

Pv-LDH 5 ng/mL

B

B

7/B

Pf Sensitivity test(NIBSC 16/376)

PF 50 IU/mL

4

4

B/7

PF 10 IU/mL

6

6

B/9+

PF 5 IU/mL

7

8

B/9

PF 2 IU/mL

9

9

B/B

PvSensitivity test(NIBSC 19/116)

PV 50 IU/mL

B

B

3/B

PV 10 IU/mL

B

B

5/B

PV 5 IU/mL

B

B

6/B

PV 2 IU/mL

B

B

7/B

CDC panel (Parasites/μL)

US 06F FC27/A3 2000

2+

1

B/1

US 06F FC27/A3 200

5

3

B/3-

US 06F FC27/A3 20

9

7

B/8+

US 06F SANTA LUCIA 2000

3

2

B/2

US 06F SANTA LUCIA 200

7

4

B/4

US 06F SANTA LUCIA 20

9

8

B/9+

US 07F BENIN I 2000

2

1

B/2+

US 07F BENIN I 200

5

2

B/4

US 07F BENIN I 20

8

6+

B/7

US 07F PHI 2000

2

1

B/2+

US 07F PHI 200

5

3

B/3-

US 07F PHI 20

B+

8

B/8-

US 10F Nigeria XII 2000

2

1

B/2+

US 10F Nigeria XII 200

5

3

B/3-

US 10F Nigeria XII 20

9

7

B/8

CDC mixed sample 200

4+

/

/

CDC mixed sample 20

8

/

/

Specificity

n=200

0/200

1/200

0/200

*Patents have been applied for Fapon’s malaria raw material series.

Colloidal Gold Standard Color Card


In addition to improving the sensitivity of Pf LDH, WHO also suggests improving the diagnosis through changes in product forms. Currently, the most recommended product form is the mix of Pf LDH+HRP2 and the combination of this mixed form and LDH-PV.


Fapon not only provides relevant raw material recommendations for traditional product combinations, but also introduces raw material solutions for new product forms, helping customers quickly complete new product development.


Traditional combinations (Left) and WHO new recommendations (Right)

Fapon offers options above



Fapon remains steadfast in its commitment to combat malaria by providing innovative and high-performance raw materials for diagnostic purposes. With our dedication to quality and adherence to global standards, we aim to play a significant role in the global effort to control and eventually eradicate malaria. Join us in the fight against this deadly disease, as together, we strive for a malaria-free world.


To learn more about our products, please visit our website https://en.faponbiotech.com/  or contact us at market@fapon.com.




Appendix

Other raw material products for Malaria diagnosis

Project

Recommended Pairs

Catalog No.

Source

Clonal No.

Subtype

Blocker

Application

MA-HRPII-Pf

Pair 1

BRCMALS107

CHO

33C4

IgM

HIER-R-001

Coating

BRJMALS109

Mouse

18F7

IgG1

Conjugating

Pair 2

BRCMALS106

CHO

35A2

IgG1

HIER-R-001

Coating

BRJMALS109

Mouse

18F7

IgG

Conjugating

Pair 3

BRCMALS105

Mouse

7A11

IgM

HIER-R-001

Coating

BRJMALS106

Mouse

2B4

IgG1

Conjugating

Pair 4

BRCMALS105

Mouse

7A11

IgM

HIER-R-001

Coating

BRCMALS104

Mouse

7A3

IgG1

Conjugating

Pair 5

BRCMALS105

Mouse

7A11

IgM

HIER-R-001

Coating

BRJMALS107

Mouse

4A4

IgG1

Conjugating

Others

BRJMALS108

CHO

35H6

IgG1

/

Conjugating

MA-PLDH-PV

Pair 1

BRCMALS216

CHO

22D5

IgM

HIER-R-040 or HIER-R-039

Coating

BRNMALN202

CHO

25F8

IgM

Conjugating

Pair 2

BRCMALS216

CHO

22D5

IgM

HIER-M-004

Coating

BRCMALS211

Mouse

5B8

IgG1

Conjugating

Pair 3

BRCMALS213

Mouse

4C6

IgG2a

HIER-M-004

Coating

BRCMALS211

Mouse

5B8

IgG1

Conjugating

MA-PLDH-PAN

Pair 1

BRCMALS215

CHO

22D5

IgM

HIER-R040

Coating

BRJMALS214

CHO

37A8

IgG1

Conjugating

Pair 2

BRCMALS216

CHO

22D5

IgM

HIER-M-004

Coating

BRJMALS210

CHO

25C7

IgG1

Conjugating

Pair 3

BRCMALS216

CHO

22D5

IgM

HIER-M-004

Coating

BRJMALS212

CHO

--

--

Conjugating

Pair 4

BRCMALS216

CHO

22D5

IgM

HIER-M-004

Coating

BRJMALS204

Mouse

8A11

IgG1

Conjugating

Pair 5

BRCMALS213

Mouse

4C6

IgG2a

HIER-M-004

Coating

BRJMALS204

Mouse

8A11

IgG1

Conjugating

Pair 6

BRCMALS216

CHO

22D5

IgM

HIER-M-004

Coating

BRJMALS202

Mouse

1A5

IgG1

Conjugating

MA-PAN-PLDH+HRPII

Pair 1

BRCMALS216

CHO

22D5

IgM

HIER-M-004

Coating

BRCMALS107

CHO

33C4

IgM

Coating

BRJMALS210

CHO

25C7

IgG1

Conjugating

BRJMALS109

Mouse

18F7

IgG

Conjugating

Pair 2

BRCMALS213

Mouse

4C6

IgG2a

HIER-M-004

Coating

BRCMALS105

Mouse

7A11

IgM

Coating

BRJMALS204

Mouse

8A11

IgG1

Conjugating

BRJMALS106

Mouse

2B4

IgG1

Conjugating




Reference

1.      Malaria. World Health Organization. Available at: https://www.who.int/zh/news-room/fact-sheets/detail/malaria (Accessed: 22 April 2024).

2.      McCaffery, J.N. et al. (2021) Plasmodium falciparum PFHRP2 and PFHRP3 gene deletions among patients in the DRC enrolled from 2017 to 2018, Nature News. Available at: https://www.nature.com/articles/s41598-021-02452-3?error=cookies_not_supported&code=02e52307-d444-473f-8c7f-dfd03d02a609 (Accessed: 22 April 2024).

3.      Sabin, S. et al. (2023) Portable and cost-effective genetic detection and characterization of Plasmodium falciparum HRP2 using the minion sequencer, Nature News. Available at: https://www.nature.com/articles/s41598-022-26935-z (Accessed: 22 April 2024).

4.      Selecting and procuring malaria RDTS. Available at: https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests/selection-and-procurement (Accessed: 22 April 2024).