Fever for 3 Days? Which Blood Tests Are Required
Share
A fever that persists for 3 days or more is one of the most common reasons families in Pune and across India visit a doctor or search for guidance online. Continuous high temperature lasting 72 hours or beyond is the primary symptom that signals the body is fighting an active infection requiring laboratory investigation to identify the cause.
Prolonged fever lasting three or more days may indicate bacterial infection, viral illness, or a mosquito-borne disease — conditions that require specific blood tests to confirm before treatment begins. Without accurate diagnosis, doctors cannot safely prescribe antibiotics or antivirals, making early blood testing a critical first step in fever management.
Fever Blood Tests in Pune
healthcare nt sickcare offers blood tests for fever and viral diseases in Pune with home sample collection and direct walk-in facility.
Why Blood Tests Are Needed After 3 Days of Fever?
Blood tests after 3 days of continuous fever help identify whether the cause is bacterial, viral, or parasitic — each requiring a different treatment approach.
The human body's immune response to infection causes temperature elevation (pyrexia — medically defined as body temperature above 38°C or 100.4°F). In the first 24–48 hours, most fevers are self-limiting viral illnesses that resolve without medication. However, when fever persists beyond 72 hours, the likelihood of a specific identifiable infection increases significantly. In Pune and Maharashtra, seasonal diseases including dengue fever, malaria, typhoid, and leptospirosis are common causes of prolonged fever — particularly during and after monsoon season. According to the World Health Organization, early laboratory confirmation of dengue and similar mosquito-borne fevers is essential to prevent life-threatening complications.
First-Line Blood Tests Recommended for 3-Day Fever
A Complete Blood Count (CBC) is the single most important first test ordered for any fever lasting 3 days, as it reveals infection type, severity, and platelet status in one report.
Complete Blood Count (CBC)
CBC (Complete Blood Count — a comprehensive blood test measuring red cells, white cells, platelets, haemoglobin, and differential white cell count) is the essential starting point for evaluating any prolonged fever. A raised total white blood cell count (leukocytosis) suggests bacterial infection, whilst a low white cell count (leucopenia) is characteristic of viral infections including dengue and typhoid. Critically, a falling platelet count (thrombocytopenia) alongside fever is an urgent warning sign for dengue haemorrhagic fever — a serious complication seen in Pune patients each monsoon season. Read our detailed explanation of fever causes, blood tests, and treatment options for broader context.
Dengue NS1 Antigen and Dengue IgM/IgG Antibody Test
Dengue NS1 antigen testing is most accurate in the first 5 days of fever onset, whilst IgM antibody testing becomes positive from day 4–5 onwards.
Dengue fever (a mosquito-borne viral illness caused by the Dengue virus transmitted by Aedes aegypti mosquitoes) is one of the most common causes of fever exceeding 3 days in Pune, especially between July and November. The NS1 antigen test detects the virus directly in the early phase, whilst IgM/IgG antibody tests confirm infection in the later phase. Both tests are frequently combined for maximum diagnostic accuracy. For a comprehensive overview of mosquito-transmitted fever testing, read our guide on testing for mosquito-borne viral fevers in India.
Malaria Antigen Test (Rapid Card Test and Peripheral Smear)
Malaria testing is essential for any fever with chills and rigors lasting more than 2 days, particularly in patients with travel history to rural Maharashtra, Goa, or tribal areas.
The malaria rapid antigen card test detects Plasmodium falciparum (the most dangerous malaria species) and Plasmodium vivax antigens within 15–20 minutes. A peripheral blood smear examination by a trained pathologist remains the gold standard for confirming species and parasite density. Both tests are usually advised together when malaria is clinically suspected.
Typhoid Test — Widal and Typhidot
Typhoid fever caused by Salmonella typhi typically presents with fever that stepwise increases over 3–5 days, often accompanied by abdominal discomfort and loss of appetite.
The Widal test (a serological agglutination test measuring antibodies against Salmonella typhi and Salmonella paratyphi) has been used for decades but has limitations in areas of high endemicity like India, where baseline antibody titres may already be elevated. The Typhidot test, which detects IgM and IgG antibodies specifically against a 50kD outer membrane protein of Salmonella typhi, offers better specificity. Blood culture remains the most definitive test for typhoid but requires 3–5 days for results.
Additional Blood Tests Based on Clinical Symptoms
If first-line tests return normal or borderline results and fever continues, doctors expand the investigation based on accompanying symptoms.
Liver Function Test (LFT)
Raised liver enzymes (transaminases) during fever indicate hepatitis, leptospirosis, dengue with liver involvement, or drug-induced liver injury — all of which require specific management beyond standard fever treatment.
C-Reactive Protein (CRP) and ESR
CRP (C-Reactive Protein — an acute-phase protein produced by the liver in response to inflammation) rises sharply within 6–12 hours of bacterial infection or tissue damage, making it one of the most sensitive early markers of serious infection. ESR (Erythrocyte Sedimentation Rate) rises more slowly and indicates chronic or ongoing inflammation. Together, CRP and ESR help doctors differentiate bacterial from viral fever and monitor treatment response.
Urine Routine and Microscopy
A urine routine test is advised when fever is accompanied by burning urination, back pain, or urinary frequency, as urinary tract infections (UTIs) are a common but frequently overlooked cause of persistent fever, especially in women and elderly patients in India.
Leptospira IgM Antibody Test
Leptospirosis (a bacterial infection spread through contact with water or soil contaminated by infected animal urine) is endemic in Maharashtra, particularly after flooding. It presents with high fever, severe muscle pain, and red eyes. The Leptospira IgM ELISA test becomes positive from day 5–7 of illness and is an important addition to the fever panel during and after monsoon season in Pune.
Fever Tests Based on Season and Location in Pune
The most likely cause of 3-day fever in Pune changes with season — making seasonal and location-aware test selection important for faster diagnosis.
During monsoon (July–September), dengue, malaria, and leptospirosis dominate. In winter (November–February), influenza and upper respiratory viral fevers are more prevalent. Year-round, typhoid and urinary tract infections remain consistent causes. Patients in areas like Wakad, Hinjewadi, Baner, and Aundh with recent flooding or waterlogging exposure should specifically request leptospira testing alongside standard fever panels. For guidance on seasonal viral illnesses, read our article on how to test for seasonal flu and cold infections.
When to Go to Hospital Instead of Waiting for Test Results?
Certain warning signs alongside 3-day fever require immediate hospital emergency evaluation and should not wait for blood test results.
These include fever above 103°F (39.4°C) unresponsive to paracetamol, severe headache with neck stiffness, skin rash appearing with fever, breathlessness or chest pain, confusion or altered consciousness, bleeding from gums or nose, inability to retain fluids due to vomiting, or fever in infants below 3 months. In these situations, call emergency services or go directly to a hospital rather than waiting for home collection appointments. For understanding fever patterns that recur, read our detailed guide on fever at night gone in morning.
Booking Fever Blood Tests in Pune
Residents across Pune can book all fever-related blood tests with home sample collection or direct walk-in without prior appointment at healthcare nt sickcare's partner NABL-accredited collection centres.
Home sample collection is available across Aundh, Baner, Wakad, Hinjewadi, Balewadi, Pimple Saudagar, Kothrud, Deccan, and surrounding areas within 10 km radius. Most fever panel reports are available within 24 hours, with dengue and malaria tests available on priority. For understanding viral infection testing more broadly, read our article on how to test for viral infections. If seasonal allergies may be contributing to your symptoms, our guide on testing for seasonal allergies may also be helpful.
Frequently Asked Questions
Disclaimer: This article is for informational and educational purposes only and does not constitute medical advice. Fever investigation and treatment decisions must always be made by a qualified medical professional based on clinical examination and laboratory findings. If fever is severe, worsening, or accompanied by warning signs, seek emergency medical care immediately. Images used on test pages are AI-generated via Google Gemini and Shopify Magic. Read our full disclaimer policy. © healthcare nt sickcare and healthcarentsickcare.com, 2017–Present.