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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Hemorrhagic Fever with Renal Syndrome

Confirming the Diagnosis: How Doctors Know It's HFRS

At a Glance

Hemorrhagic Fever with Renal Syndrome (HFRS) is definitively diagnosed using RT-PCR or antibody blood tests to detect the hantavirus. Doctors also look for a specific clinical triad of fever, low blood platelets (thrombocytopenia), and signs of kidney injury like protein in the urine.

Diagnosing Hemorrhagic Fever with Renal Syndrome (HFRS) can be challenging because its early symptoms—fever, headache, and body aches—mimic many other common infections. To confirm HFRS, doctors look for a specific “triad” of findings: fever, evidence of bleeding or low platelets, and signs of kidney injury [1][2].

The Definitive Tests

To know for certain that you have HFRS, your healthcare team will perform specific laboratory tests:

  • Serology (Antibody Tests): This is the most common method. The lab looks for IgM and IgG antibodies produced by your immune system to fight the hantavirus [3]. IgM antibodies appear very early in the infection, while IgG antibodies develop a bit later and provide long-term memory of the virus [4].
  • PCR (Molecular Testing): A Reverse Transcription-Polymerase Chain Reaction (RT-PCR) test can detect the actual genetic material (RNA) of the virus in your blood [5]. This is highly accurate and can often confirm the diagnosis in the very first days of the illness, sometimes even before your body has produced enough antibodies to be detected [6].

Hallmark Findings in Your Labs

Beyond the virus tests, your doctors will watch several key markers to track how your body is handling the infection:

  1. Thrombocytopenia (Low Platelets): Platelets are the cells that help your blood clot. A sharp drop in your platelet count is a signature sign of HFRS [2]. The lower the count, the more carefully your team will watch for signs of bleeding [7].
  2. Proteinuria (Protein in Urine): Healthy kidneys keep protein in your blood. In HFRS, the kidneys become “leaky,” allowing large amounts of protein to spill into your urine [8][9].
  3. Elevated Creatinine: Creatinine is a waste product that your kidneys normally filter out. If your blood levels of creatinine rise, it indicates that your kidneys are under stress and not filtering efficiently [10].

Differentiating HFRS from Similar Diseases

In many parts of the world where HFRS is found, other diseases can look very similar. Your doctor must rule these out to ensure you get the right treatment:

  • Scrub Typhus: This is spread by mites. Unlike HFRS, it often leaves a “black scab” (called an eschar) where the mite bit you [11].
  • Leptospirosis: This bacterial infection also causes kidney issues and fever. However, it often causes severe calf pain and yellowing of the eyes (jaundice), which are less common in HFRS [12][13].
  • Dengue Fever: Dengue also causes high fever and low platelets. However, Dengue is less likely to cause the severe kidney injury that is the hallmark of HFRS [14].
  • SFTS (Severe Fever with Thrombocytopenia Syndrome): This is a tick-borne virus that looks almost identical to HFRS in the early stages. Doctors use PCR testing to tell them apart, as SFTS does not usually cause the same specific type of kidney “leakiness” as HFRS [15][16].

Your Diagnostic Checklist

You can ask your nurse or doctor if the following tests have been completed or are in your chart:

  • [ ] Hantavirus IgM and IgG (Serology)
  • [ ] Hantavirus RT-PCR (Molecular test)
  • [ ] Complete Blood Count (CBC) (To check platelet and white blood cell levels)
  • [ ] Comprehensive Metabolic Panel (CMP) (To check creatinine and kidney function)
  • [ ] Urinalysis (To check for protein and blood)
  • [ ] Inflammation Markers (Such as CRP or Procalcitonin, to monitor severity)

Common questions in this guide

How do doctors confirm an HFRS diagnosis?
Doctors confirm HFRS using specific blood tests, primarily serology for IgM and IgG antibodies or an RT-PCR test to detect the hantavirus genetic material. They also look for a clinical pattern of fever, low platelets, and signs of kidney injury.
What is the difference between an antibody test and a PCR test for HFRS?
An RT-PCR test detects the actual genetic material of the hantavirus and can confirm the infection very early on. Antibody tests look for the immune system's response to the virus, which develops slightly later.
Why are my platelets dropping with HFRS?
A sharp drop in blood platelets, known as thrombocytopenia, is a signature sign of HFRS. Since platelets help blood clot, your healthcare team will monitor your levels closely to watch for any signs of bleeding.
What does protein in the urine mean for HFRS patients?
Protein in the urine, or proteinuria, indicates that the kidneys are under stress and becoming 'leaky.' It is a key sign of the kidney injury commonly caused by Hemorrhagic Fever with Renal Syndrome.
How do doctors know I have HFRS and not Dengue or Leptospirosis?
Doctors use specific lab tests like RT-PCR to distinguish HFRS from similar diseases. They also look for specific symptoms; for instance, leptospirosis often causes severe calf pain and jaundice, which are less common in HFRS.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Has my HFRS diagnosis been confirmed by a PCR test or by an antibody test (IgM/IgG)?
  2. 2.Is my platelet count still dropping, and at what level would you consider a transfusion?
  3. 3.What does my urinalysis show regarding protein and blood?
  4. 4.How are you ruling out other similar illnesses like leptospirosis or scrub typhus in my case?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (16)
  1. 1

    [Seoul hantavirus infection-associated hemorrhagic fever with renal syndrome in France: A case report].

    Bour A, Reynes JM, Plaisancie X, Dufour JF

    La Revue de medecine interne 2016; (37(7)):493-6.

    PMID: 26971198
  2. 2

    [The efficiency of modernmethods of laboratory diagnosis in the evaluation of various forms of hemorrhagic fever with renal syndrome caused by the Puumala hantavirus (PUUV).]

    Mukhetdinova GA, Fazlyeva RM, Mavzyutova GA, et al.

    Klinicheskaia laboratornaia diagnostika 2018; (63(9)):524-529 doi:10.18821/0869-2084-2018-63-9-524-529.

    PMID: 30735316
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    Acute hantavirus infection presenting as haemolytic-uraemic syndrome (HUS): the importance of early clinical diagnosis.

    Clement J, Lee APK, Verpooten GA, et al.

    European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology 2018; (37(1)):135-140 doi:10.1007/s10096-017-3113-6.

    PMID: 28986730
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    Case Report: Hemorrhagic Fever with Renal Syndrome Complicated by Bilateral Subdural Hematoma.

    Xiao W, Tang Y, Chen L, et al.

    The American journal of tropical medicine and hygiene 2023; (109(6)):1339-1343 doi:10.4269/ajtmh.23-0248.

    PMID: 37931317
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    Molecular Diagnosis of Hemorrhagic Fever with Renal Syndrome Caused by Puumala Virus.

    Lagerqvist N, Hagström Å, Lundahl M, et al.

    Journal of clinical microbiology 2016; (54(5)):1335-9 doi:10.1128/JCM.00113-16.

    PMID: 26962084
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    Utility of Nested Reverse-Transcriptase Polymerase Chain Reaction of Clinical Specimens for Early Diagnosis of Hemorrhagic Fever with Renal Syndrome.

    Seo JW, Kim DY, Kim CM, et al.

    The American journal of tropical medicine and hygiene 2021; (105(5)):1285-1289.

    PMID: 34370707
  7. 7

    Analysis of misdiagnosed cases of hemorrhagic fever with renal syndrome in children: two cases and literature review.

    Zhang L, Ma QS, Zhang Y, et al.

    BMC nephrology 2019; (20(1)):383 doi:10.1186/s12882-019-1562-0.

    PMID: 31646967
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    Glomerular Injury Is Associated with Severe Courses of Orthohantavirus Infection.

    Nusshag C, Uhrig J, Gruber G, et al.

    Pathogens (Basel, Switzerland) 2024; (13(8)) doi:10.3390/pathogens13080693.

    PMID: 39204293
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    Neutrophil-to-lymphocyte ratio is elevated in acute hantavirus infection and correlates with markers of disease severity.

    Nusshag C, Gruber G, Zeier M, Krautkrämer E

    Journal of medical virology 2024; (96(6)):e29759 doi:10.1002/jmv.29759.

    PMID: 38899399
  10. 10

    FDG PET/CT in Hantavirus Hemorrhagic Fever With Renal Syndrome.

    Han YH, Lee CS

    Clinical nuclear medicine 2023; (48(12)):1073-1075 doi:10.1097/RLU.0000000000004915.

    PMID: 37934706
  11. 11

    Misdiagnosis of scrub typhus as hemorrhagic fever with renal syndrome and potential co-infection of both diseases in patients in Shandong Province, China, 2013-2014.

    Gu XL, Qi R, Li WQ, et al.

    PLoS neglected tropical diseases 2021; (15(3)):e0009270 doi:10.1371/journal.pntd.0009270.

    PMID: 33784301
  12. 12

    Hantavirus Hemorrhagic Fever with Renal Syndrome - Suspected Cases in Sri Lanka: Clinical Picture and Epidemiology from 2013-2021.

    Muthugala R, Dheerasekara K, Manamperi A, et al.

    Japanese journal of infectious diseases 2022; (75(5)):533-536 doi:10.7883/yoken.JJID.2021.837.

    PMID: 35491227
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    Hantavirus Infection in Children-A Pilot Study of Single Regional Center.

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    PMID: 37112856
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    Pathogenicity and virulence of Rodent-Borne Orthohantaviruses.

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    The Differential Characteristics Between Severe Fever With Thrombocytopenia Syndrome and Hemorrhagic Fever With Renal Syndrome in the Endemic Regions.

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    Open forum infectious diseases 2019; (6(12)):ofz477 doi:10.1093/ofid/ofz477.

    PMID: 32128325
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    Severe fever with thrombocytopenia syndrome can masquerade as hemorrhagic fever with renal syndrome.

    Qi R, Qin XR, Wang L, et al.

    PLoS neglected tropical diseases 2019; (13(3)):e0007308 doi:10.1371/journal.pntd.0007308.

    PMID: 30925154

This page explains HFRS diagnostic tests for educational purposes. Always consult your healthcare provider to accurately interpret your specific lab results and symptoms.

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