Home Health Centre Dengue Dengue Fever From Rapid Kits to Blood Tests: Learn the Many Ways to Check for Dengue!

From Rapid Kits to Blood Tests: Learn the Many Ways to Check for Dengue!

Exploring Various Dengue Testing Methods, From Rapid Kits to Blood Tests | DoctorOnCall

Dengue fever, a mosquito-borne viral infection, poses a significant health threat in many parts of the world.[1] Characterised by high fever, severe headaches, joint pain, and rash, dengue symptoms can range from mild to severe, and in extreme cases, can even be life-threatening.[1]With its prevalence on the rise, understanding how to diagnose dengue becomes crucial for timely intervention.[1]

What Is a Dengue Test?

A dengue test is a diagnostic procedure used to identify the presence of the dengue virus or antibodies produced in response to the virus in a patient's blood.[2] This test helps in confirming whether an individual is infected with dengue or not.[2] 

What to Know Before Testing?

​Before undergoing testing for dengue, there are several crucial factors to consider. Being aware of these aspects ensures that the test results are accurate and meaningful. Here are the key factors to know before testing for dengue:

  • Timing of Testing

The timing of the dengue test is crucial for obtaining accurate results.[3] Testing too early may yield false-negative results as the virus may not be detectable in the initial stages of infection.[3] Consult your healthcare provider for the suitable testing type based on your exposure time.

  • Medical History and Medications

Disclosing any pre-existing medical conditions or ongoing medications is vital. A comprehensive medical history ensures the healthcare provider can interpret the results accurately.

  • Consult a Healthcare Professional

Before undergoing any dengue testing, it is crucial to consult a qualified healthcare professional, such as a doctor or nurse.[4] They have the expertise to guide you through the testing process, interpret the results, and provide appropriate recommendations based on your specific situation.[4]

Types of Dengue Tests

When it comes to diagnosing dengue, various tests are employed to provide accurate results. Each type serves a specific purpose in detecting the presence of the virus or its effects on the body. Here's an in-depth overview of these tests:

Diagnostic Tests

1. IgM and IgG

These tests identify specific antibodies produced by the immune system in response to the dengue virus.[5] They indicate whether an individual has been previously exposed to dengue and developed immunity to the relevant serotype.[3] 

Serologic tests also assist in confirming an active dengue infection by detecting dengue-specific antibodies in the blood.[5]

The types of dengue serology tests include:

  • Haemagglutination Inhibition Test
  • Dengue IgM test
  • Indirect IgG ELISA test

2. Molecular Tests (PCR):

Molecular tests employ advanced techniques, such as polymerase chain reaction (PCR), to detect the genetic material (RNA) of the dengue virus.[5][6] Highly sensitive and specific, these tests directly identify the virus itself.[5] They are particularly effective in the early stages of infection when the viral load is higher, providing a definitive diagnosis of an active dengue infection.[5]

It's worth noting that although PCR is a powerful tool, it is uncommon for the routine clinical diagnosis of patients.

3. Dengue Virus Antigen Detection (NS1):

The NS1 antigen detection test is a rapid diagnostic tool that identifies a specific viral protein called non-structural protein 1 (NS1) in the blood.[5] NS1 is produced by the dengue virus early in the infection and can be detected before antibodies are generated by the immune system.[5] This characteristic makes the test crucial for the early diagnosis of dengue.[5] Notably, NS1 can be detected as early as the second day until the seventh day after the onset of fever.

4. Rapid NS1 Ag and IgG/IgM Ab Test for Dengue

This test t is a reliable qualitative membrane-based immunoassay designed for the identification of NS1 antigen and IgG/IgM antibodies in human serum, plasma, or whole blood. The test kit comprises two devices – one for detecting the dengue NS1 antigen and another for the differential detection of dengue IgG/IgM antibodies. 

Routine Blood Test Monitoring(FBC)

A full blood count, or FBC, is a comprehensive blood test. It scrutinises vital blood components, including red blood cells, white blood cells, and platelets.[5] 

  • White Cell Count (WCC): Initially normal in dengue, it decreases as the disease advances, indicating possible infection.[5] 
  • Haematocrit (HCT): Rises with plasma leakage in dengue, helping differentiate between Dengue Fever (DF) and Dengue Hemorrhagic Fever (DHF). Baseline HCT in the early febrile phase aids in recognising a rising level.[5] 
  • Thrombocytopaenia: Common in dengue; though platelet count is normal in the early febrile phase, it decreases rapidly as the disease progresses and may remain low during recovery. The severity of the disease negatively correlates with platelet count.[5]

These tests collectively form a crucial arsenal in the fight against dengue. They provide healthcare professionals with essential information to make informed decisions regarding treatment and monitor the progression of the infection.[5] The choice of test may depend on factors like the stage of infection and the patient's clinical presentation.[5]

Results Interpretation

Once a dengue test has been conducted, it's important to understand how to interpret the results. Here's a guide to help you make sense of the outcomes:

  • Positive Result: This means the dengue virus or antibodies were found. It indicates an active dengue infection.[5] 
  • Negative Result (Early Stage): In the early stages, a negative result might not rule out dengue. It can take time for the virus or antibodies to show up.[7]
  • Positive Result in Serologic Tests: A positive result in serologic tests suggests previous exposure to dengue but doesn't necessarily mean an active infection. It could indicate immunity developed to the relevant serotype from a past encounter with the virus. Confirmatory tests may be needed to assess the current infection status.[7][8]

The test outcomes may not mark the conclusion of the journey; both positive and negative results could be inaccurate, necessitating additional testing.[7]

Consult with a healthcare provider as they are the best to explain what your results mean for your specific situation,[4] and monitor symptoms. Regardless of results, keep an eye on any dengue-like symptoms, and if they worsen or persist, seek medical help.[5]

Remember, dengue testing is just one piece of the puzzle. Clinical evaluation by a healthcare professional is essential for accurate diagnosis and appropriate treatment.[4]

Who Needs Testing?

To effectively combat the spread of dengue, it is vital to recommend testing for all individuals exhibiting dengue-like symptoms as a priority.[7]Additionally, other specific groups should also consider testing under certain circumstances:[7]

  • Recent travellers to dengue-prone areas[6]
  • Residents of dengue-prone regions[7]
  • Individuals with compromised immune systems[9]
  • Pregnant women[10]

How Much Does It Cost?

The cost of dengue testing can vary based on the type of test, location, and healthcare provider. Generally, serologic tests are more affordable compared to molecular tests or specialised kits.[11]It's advisable to check with local healthcare facilities for specific pricing.

Where to Get Tested?

Dengue testing is available at various healthcare institutions, including hospitals, clinics, and specialised diagnostic centres.[12] Local health authorities often provide information on testing locations, especially in areas prone to dengue outbreaks.[13]

Safeguarding Health in the Face of the Dengue Threat!

Early detection of dengue through appropriate testing is crucial for effective management and timely medical intervention.[3] 

Understanding the types of tests available and their significance aids in making informed healthcare decisions. If you suspect you or a loved one has dengue, don't hesitate to consult a healthcare professional and get tested promptly.

References

  1. World Health Organization (WHO). “Dengue and severe dengue.” World Health Organization (WHO), 17 March 2023, https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue. Accessed 26 September 2023.
  2. Myhealth Gov. “What is Dengue – DENGGI.” Myhealth, 24 February 2016, http://denggi.myhealth.gov.my/what-is-dengue/?lang=en. Accessed 26 September 2023.
  3. NCBI. “LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS - Dengue.” NCBI, https://www.ncbi.nlm.nih.gov/books/NBK143156/. Accessed 26 September 2023.
  4. LCS, Lum. “Managing dengue fever in primary care: A practical approach.” NCBI, 31 August 2014, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4399402/. Accessed 26 September 2023.
  5. Kementerian Kesihatan Malaysia. “CPG - Dengue New Revised edition (new).indd.” Kementerian Kesihatan Malaysia, https://www.moh.gov.my/moh/attachments/5502.pdf. Accessed 26 September 2023.
  6. NCBI. “Simple technique for detecting RNA viruses by PCR in single sections of wax embedded tissue.” NCBI, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC501187/. Accessed 26 September 2023.
  7. CDC. “Testing Guidance | Dengue.” CDC, https://www.cdc.gov/dengue/healthcare-providers/testing/testing-guidance.html. Accessed 26 September 2023.
  8. CDC. “Dengue Virus Antigen Detection | Dengue.” CDC, 3 May 2019, https://www.cdc.gov/dengue/healthcare-providers/testing/antigen-detection.html. Accessed 26 September 2023.
  9. NCBI. “Chikungunya, Dengue, and Zika in Immunocompromised Hosts.” NCBI, 17 March 2018, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5857271/. Accessed 26 September 2023.
  10. NCBI. “Maternal and fetal outcomes of dengue fever in pregnancy: a large prospective and descriptive observational study.” NCBI, 2 January 2021, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7778400/. Accessed 26 September 2023.
  11. NCBI. “Dengue Detection: Advances in Diagnostic Tools from Conventional Technology to Point of Care.” NCBI, 23 June 2021, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8301808/. Accessed 26 September 2023.
  12. MyHEALTH Kementerian Kesihatan Malaysia. “Ujian Denggi - PORTAL MyHEALTH.” MyHEALTH Kementerian Kesihatan Malaysia, 26 February 2014, http://www.myhealth.gov.my/ujian-denggi/. Accessed 26 September 2023.
  13. Info Sihat. “GARIS PANDUAN.” Info Sihat, 24 April 2021, https://www.infosihat.gov.my/images/media_sihat/garis_panduan/pdf/Buku%20Denggi%20PAKAT.pdf. Accessed 26 September 2023.

This article is brought to you by Takeda Malaysia Sdn. Bhd. 200901025887 (868989-K)

Disclaimer: This information is available to the public for information purposes only; it should not be used for diagnosing or treating a health problem or disease. It is not intended to substitute consultation with a healthcare provider. Please consult your healthcare provider for advice.

C-ANPROM/MY/DENV/0240 DEC 2023


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Written By Dr Shobika Nair, Doctor of Medicine, I.M. Sechenov First Moscow State Medical University, Russia on

Reviewed By DoctorOnCall Panel Doctor