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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.

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Importance of Hydration for Organs: How Water Keeps the Body Functioning

Water is the most essential nutrient for human survival, yet it is often the most neglected. Every cell, tissue and organ in the body depends on adequate hydration to function properly. The importance of hydration for organs becomes clear when we understand how even mild dehydration can disrupt critical physiological processes.

In India’s climate, with high temperatures and humidity in many regions, dehydration risk is especially high, making conscious hydration a daily health priority.

Why Water Is Vital for the Human Body

The human body is made up of approximately 60 percent water. This water:

transports nutrients and oxygen
regulates body temperature
removes waste products
supports metabolic reactions

Without adequate hydration, organ systems begin to struggle.

Hydration and Kidney Health

The kidneys are among the most hydration-dependent organs.

Proper hydration:

helps kidneys filter blood efficiently
flushes out toxins and waste
reduces risk of kidney stones

Chronic dehydration forces kidneys to concentrate urine, increasing strain and long-term damage risk. According to Indian Council of Medical Research data, dehydration is a major contributor to kidney stone formation in India.

Brain Function and Hydration

The brain is highly sensitive to hydration levels.

Even mild dehydration can cause:

headaches
difficulty concentrating
memory issues
irritability

Studies published in the Lancet show that dehydration negatively affects cognitive performance and mood, even before thirst becomes noticeable.

Heart and Circulatory System

Hydration plays a critical role in cardiovascular health.

Adequate water intake:

maintains blood volume
supports smooth circulation
reduces strain on the heart

Dehydration thickens blood, making the heart work harder and potentially increasing the risk of low blood pressure, dizziness and cardiovascular stress.

Digestive System and Hydration

Water supports digestion at every stage.

It helps:

break down food
absorb nutrients
prevent constipation

Chronic low water intake is linked to digestive discomfort, bloating and poor gut motility.

Liver Function and Detoxification

The liver relies on water to:

metabolise nutrients
detoxify harmful substances
support metabolic balance

Inadequate hydration slows detoxification processes and increases metabolic strain.

Muscle and Joint Health

Muscles and joints contain significant water content.

Hydration:

prevents muscle cramps
supports joint lubrication
reduces injury risk

Dehydrated muscles fatigue faster and recover more slowly.

Skin as an Organ and Hydration

The skin is the body’s largest organ.

Adequate hydration:

maintains skin elasticity
supports barrier function
reduces dryness and irritation

While water alone is not a cure for skin problems, chronic dehydration worsens skin health.

Hydration and Immune Function

Water supports immune health by:

enabling transport of immune cells
aiding removal of toxins
supporting lymphatic circulation

WHO recognises hydration as a foundational element of immune system support.

Effects of Dehydration on Multiple Organs

Dehydration affects the body systemically.

Common effects include:

fatigue
dizziness
reduced urine output
dark-coloured urine
dry mouth and eyes

Severe dehydration can lead to organ failure if untreated.

Why Dehydration Often Goes Unnoticed

Many people confuse thirst with hunger or fatigue.

Risk factors include:

busy work schedules
excessive caffeine intake
high temperatures
inadequate fluid intake

By the time thirst is felt, dehydration has already begun.

Hydration Needs Vary by Individual

Water requirements depend on:

age
body size
physical activity
climate
health conditions

General guidelines suggest 2–3 litres daily for adults, but individual needs may vary.

Hydration and Chronic Disease Prevention

Proper hydration supports prevention of:

kidney disease
urinary tract infections
constipation
heat-related illness

NITI Aayog and WHO highlight hydration as a basic preventive health measure.

Best Practices for Staying Hydrated

Effective hydration strategies include:

drinking water regularly throughout the day
increasing intake during heat or physical activity
consuming water-rich foods such as fruits and vegetables
limiting sugary and caffeinated beverages

Consistency matters more than quantity in a single sitting.

Signs You May Need More Water

Watch for:

frequent fatigue
headaches
dry skin
reduced urination
poor concentration

These are early indicators of dehydration.

Role of Preventive Health Awareness

Preventive healthcare focuses on simple daily habits.

Hydration:

costs nothing
supports every organ
reduces disease risk

Small habits deliver large long-term benefits.

When to Seek Medical Advice

Consult a healthcare professional if experiencing:

persistent dehydration symptoms
kidney or urinary issues
dizziness or fainting
chronic fatigue

Underlying conditions may require medical evaluation.

Conclusion

The importance of hydration for organs cannot be overstated. Water supports kidney filtration, brain function, heart circulation, digestion, immunity and overall metabolic balance. Even mild dehydration disrupts organ performance and increases health risks over time. In busy modern lifestyles, consciously prioritising daily hydration is one of the simplest and most effective ways to protect vital organs and maintain long-term health. Consistent water intake is not just a habit—it is a foundation for organ health and wellbeing.

References

Indian Council of Medical Research (ICMR) – Hydration and Kidney Health Studies
World Health Organization (WHO) – Water Intake and Health Guidelines
National Family Health Survey (NFHS-5) – Nutrition and Lifestyle Data
Lancet – Hydration, Cognitive Function and Organ Health Research
NITI Aayog – Preventive Healthcare and Lifestyle Recommendations
Statista – Global Hydration and Health Trends

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