Q: My child tested negative for the flu but still has a high fever and a sore throat. Should we test again?

This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.

Question:

My child started having a fever on Friday evening. At night, the temperature reached 39.4°C, and after taking a fever reducer, it went down to 37.9°C. On Saturday morning, we visited the pediatrician and got a flu test, which came back negative. The doctor mentioned that my child's throat is very swollen and the fever might last for a few days.

When the fever reducer wears off, my child becomes lethargic and the temperature rises above 38°C again. Once given the medicine, the fever drops and my child's condition improves. There is no cough or other symptoms; they only complain of a sore throat. Should we get another flu test?

Answer:

You must have been worried since the symptoms continued after the test on Saturday.

【Current Situation Summary】

High fever starting Friday evening + sore throat, negative flu test on Saturday, and only a sore throat without a cough or runny nose → There is a possibility of viral pharyngitis (Adenovirus, Enterovirus, EBV, etc.) or a false negative from testing too early for the flu.

【When to Retest for the Flu】

• Within 48 hours of symptom onset + considering antiviral medication → Retesting is meaningful.

• If it has already been over 72 hours or the symptoms are improving → Observation is more reasonable than retesting.

• If the pediatrician told you, "The throat is swollen, so the fever may last for a few days" → Follow that plan first and observe, then discuss the need for a retest during your follow-up visit on Monday.

【What to Do at Home Now】

• Use fever reducers at the correct dosage only when uncomfortable (38.5°C or higher + lethargy).

• Soothe the throat with cold drinks or ice cream, and offer fluids frequently in small sips.

• Ensure plenty of rest and maintain indoor humidity at 40-60%.

【Seek Same-Day Medical Attention if Any of the Following Occur】

• The fever does not go down or gets even higher after 3-4 days.

• Signs of dehydration due to difficulty swallowing water or saliva (decreased urine output, dry lips).

• Difficulty breathing, voice changes, or drooling.

• Sudden extreme lack of energy or difficulty waking up.

To summarize the main point: There is a possibility of an early flu false-negative, but at this point, observing the condition over the weekend and discussing whether to retest during the Monday follow-up visit is the most efficient approach.

For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.

https://fevercoach.us