Call
+918447748545

Published on: Jul 09, 2020
2 minute read
By: Dr Rakesh Choudhary

COVID- 19 Tests – What Do You Need To Know?

COVID- 19 tests – What do you need to know?

Author: Dr. Rakesh Choudhary MBBS, MS, FRCS UK, FRCS Orth UK, MChOrth UK.

Dr. Choudhary is a practicing consultant surgeon in the UK.

So many of us think it is not their job to learn about COVID-19 tests and this should be left for the experts and governments to decide about these tests. But I strongly suggest the public must have a basic understanding of these tests which they may have to have themselves.

Basically there are two types of tests, one which can detect the virus in the body and the other one which tells if the person had the previous infection.

Virus test

The virus test detects an active infection. It detects the genetic material (RNA) of the virus during an active infection. It is also called a PCR (polymerase chain reaction) test or nucleic acid test and is sometimes inaccurately called an antigen test.

A swab is taken from deep in the back of your throat and deep in the nose. The swab should go deep up to 7-8 cm and is generally uncomfortable for the patient. Swabbing patients using the correct technique is paramount in ensuring an accurate result. By simply swabbing the inside of the nasal passage is not deep enough to verify that the virus is present.

What does virus testing tell you?

This test tells us if a patient is actively infected with the COVID-19 virus. Virus testing is used mainly for the diagnosis of COVID-19.

When should it be done?

The virus test works best during the first seven days of symptoms.

The coronavirus can be detected in swabs even before symptoms of illness first appear . This is why people can be infectious for a few days before the onset of symptoms, which usually appear about 5 days after the virus infects. Some people have no symptoms throughout their infection but are positive on the virus test and infectious to others. After a few days of illness, the concentration of the virus falls (as seen in swab samples) and the symptoms of the illness usually recede.

Accuracy of the test

In a person with COVID-19, the test is less likely to give a positive result late in the course of infection once the virus has been cleared by the immune system, or if an inadequate sample is taken from the nose or throat. There are concerns that the rate of ‘false negative’ test results could be as high as 30% and a significant number of people are wrongly being told they do not have the virus.

Antibody test

Antibody tests check your blood by looking for antibodies, which may tell you if you had a past infection with the virus that causes COVID-19. Antibodies are protein structures that are produced by the immune system in response to certain infections. The antibody can help fight off infections and can provide protection against getting that disease again (immunity). Antibodies are disease-specific. For example, measles antibodies will protect you from getting measles if you are exposed to it.

The antibody test detects the presence of antibodies as a marker of past infection. The antibody test (blood test) will only detect infections after the immune system has produced antibodies that recognize the virus. This happens approximately 7–10 days after symptoms develop.

Tests carried out a week after a patient develops symptoms will detect only 30% of people who had COVID-19 infection. Accuracy increases to 72% at two weeks and to 94% in the third week. Some people may take even longer to develop antibodies, and some people who are infected may not ever develop antibodies.

Interpretation of the antibody test is complex for non-medical people. Basically having antibodies to the virus that causes COVID-19 may provide protection from getting infected with the virus again. If it does, we do not know how much protection the antibodies may provide or how long this protection may last.

Read Blog

Role of Nutrition in Disease Prevention: How Food Choices Shape Long-Term Health

Disease prevention is no longer limited to vaccinations and medical screenings. Modern healthcare increasingly recognises nutrition as one of the most powerful tools for preventing illness before it begins. The role of nutrition in disease prevention is especially important in India, where lifestyle-related diseases account for a large share of premature illness and mortality.

According to the Indian Council of Medical Research (ICMR) and the National Family Health Survey (NFHS-5), poor dietary patterns contribute significantly to rising cases of diabetes, heart disease, obesity and hypertension. Unlike genetic factors, nutrition is a modifiable risk factor, meaning everyday food choices can actively protect health.

Why Nutrition Is Central to Disease Prevention

1. Nutrition regulates metabolic health

Balanced diets help maintain:

healthy blood sugar levels
optimal cholesterol balance
stable blood pressure

Disruption in these systems increases disease risk.

2. Nutrition strengthens immunity

WHO highlights that immune function depends heavily on adequate intake of vitamins, minerals and protein.

3. Nutrition controls inflammation

Chronic low-grade inflammation is linked to most lifestyle diseases. Diets rich in whole foods reduce inflammatory markers.

Major Diseases Influenced by Nutrition

Diabetes and Prediabetes

Excess refined carbohydrates and sugar drive insulin resistance.

Preventive nutrition focuses on:

whole grains
fibre-rich vegetables
adequate protein
controlled portion sizes

ICMR data shows that dietary modification can delay or prevent type 2 diabetes in high-risk individuals.

Cardiovascular Disease

Heart disease remains a leading cause of death in India.

Nutrition impacts:

cholesterol levels
blood pressure
arterial inflammation

Diets low in trans fats and high in fibre significantly reduce cardiovascular risk, as confirmed by WHO and Lancet studies.

Obesity

Obesity increases the risk of multiple chronic diseases.

Preventive nutrition addresses:

calorie density
food quality
satiety regulation

NFHS-5 reports a steady rise in overweight and obesity across age groups.

Hypertension

High sodium intake and low potassium intake contribute to high blood pressure.

Preventive dietary strategies include:

reducing processed foods
increasing fruits and vegetables
maintaining mineral balance

Certain Cancers

Diet influences cancer risk through:

antioxidant intake
fibre consumption
reduced exposure to carcinogenic compounds

WHO estimates that a significant percentage of cancers are preventable through diet and lifestyle changes.

Key Nutrients That Support Disease Prevention

Fibre

Supports gut health, blood sugar control and cholesterol reduction.

Protein

Essential for muscle health, immune function and metabolic balance.

Healthy Fats

Omega-3 fats reduce inflammation and protect heart health.

Micronutrients

Iron, zinc, vitamin D and B vitamins are essential for metabolic and immune regulation.

NFHS-5 highlights widespread micronutrient deficiencies in India, increasing disease vulnerability.

Role of Gut Health in Prevention

The gut microbiome plays a major role in:

immune regulation
inflammation control
nutrient absorption

Fermented foods and fibre-rich diets support healthy gut bacteria, strengthening disease resistance.

Why Preventive Nutrition Works Best Early

Nutrition is most effective when applied:

before disease onset
during pre-disease stages
alongside regular health screening

Once disease progresses, nutrition remains supportive but may not reverse damage fully.

Nutrition vs Medication in Prevention

Medication treats disease; nutrition reduces risk.

WHO and NITI Aayog emphasize that:

preventive nutrition reduces disease incidence
lifestyle modification lowers healthcare burden
early nutrition changes reduce dependency on long-term medication

Both approaches work best when combined appropriately.

Workplace and Community Role in Preventive Nutrition

Structured nutrition programs at workplaces and communities:

improve awareness
support behaviour change
reduce population-level disease burden

Lancet studies show that group-based nutrition interventions improve long-term adherence.

Common Myths About Nutrition and Disease Prevention

Myth 1: Supplements replace healthy food

Whole foods provide better long-term protection.

Myth 2: Prevention requires extreme diets

Consistency matters more than restriction.

Myth 3: Nutrition only matters after diagnosis

Early nutrition is most effective before disease develops.

Building a Preventive Nutrition Routine

Effective preventive nutrition includes:

regular meals
diverse food groups
portion awareness
minimal processed foods
hydration

Small daily choices compound into long-term health benefits.

Long-Term Impact of Preventive Nutrition

Consistent healthy eating leads to:

reduced disease risk
improved energy and productivity
better immune resilience
lower healthcare costs
improved quality of life

NITI Aayog identifies nutrition as a cornerstone of sustainable healthcare systems.

Conclusion

Understanding the role of nutrition in disease prevention empowers individuals to take control of their health long before illness develops. Balanced, consistent nutrition reduces inflammation, supports immunity and protects against chronic diseases that burden India’s healthcare system. Preventive nutrition is not about short-term fixes but about building lifelong habits that support health, resilience and longevity.

References

ICMR – Nutrition and Lifestyle Disease Prevention Reports
National Family Health Survey (NFHS-5) – Dietary and Metabolic Health Data
NITI Aayog – Preventive Healthcare and Nutrition Strategy Reports
WHO – Diet, Nutrition and Chronic Disease Prevention Guidelines
Lancet – Nutrition and Disease Risk Reduction Studies
Statista – Dietary Trends and Health Outcomes India
EY-FICCI – Preventive Healthcare and Nutrition Economics

Request A Callback

+91

By using this website/app, I confirm that I am at least 18 years old and consent to the processing of my personal data in accordance with the Terms of Service, Privacy Policy, and Declaration.