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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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How Poor Hydration Affects Joint Health: Why Water Matters for Mobility

Water is essential for nearly every function in the human body, yet many people underestimate its importance for joint health. While hydration is commonly associated with digestion and skin health, it also plays a crucial role in maintaining smooth and pain-free joint movement.

Understanding how poor hydration affects joint health can help prevent stiffness, discomfort and long-term mobility issues.

The Role of Water in Joint Function

Joints are where two bones meet, allowing movement and flexibility. Healthy joints rely on:

Cartilage
Synovial fluid
Ligaments
Tendons

Cartilage, which cushions bones, contains a high percentage of water. Synovial fluid acts as a lubricant, reducing friction during movement.

Proper hydration ensures these components function effectively.

What Happens When You Are Dehydrated?

When the body lacks sufficient water:

Synovial fluid production may decrease
Cartilage may lose elasticity
Joint cushioning becomes less effective

This can result in stiffness and discomfort.

1. Reduced Joint Lubrication

Synovial fluid requires adequate hydration to maintain volume and viscosity.

Without enough water:

Friction between bones increases
Movement becomes less smooth
Risk of wear and tear rises

2. Increased Joint Stiffness

Dehydration may cause joints to feel tight, especially:

In the morning
After prolonged sitting
During physical activity

Stiffness may limit flexibility.

3. Higher Risk of Injury

Poorly lubricated joints may be more prone to:

Sprains
Strains
Cartilage damage

Hydration supports tissue resilience.

4. Worsening of Existing Joint Conditions

Individuals with conditions such as osteoarthritis may experience increased discomfort if hydration is inadequate.

While water does not cure arthritis, it supports overall joint function.

5. Reduced Nutrient Delivery

Water helps transport nutrients to joint tissues.

Dehydration may impair circulation and nutrient exchange, slowing tissue repair.

Signs of Dehydration That May Affect Joints

Dry mouth
Dark urine
Fatigue
Headaches
Muscle cramps
Joint stiffness

Recognizing early dehydration signs prevents complications.

How Much Water Do You Need?

Hydration needs vary depending on:

Body weight
Climate
Physical activity level
Health conditions

On average, adults may require 2–3 liters of water daily.

In hot climates such as India, higher intake may be necessary due to increased sweating.

Tips to Maintain Proper Hydration

1. Drink Water Regularly

Do not wait until you feel thirsty.

2. Eat Water-Rich Foods

Include:

Cucumbers
Watermelon
Oranges
Tomatoes

3. Limit Excessive Caffeine and Alcohol

These may contribute to fluid loss.

4. Carry a Water Bottle

Keeping water accessible encourages consistent intake.

5. Hydrate Before and After Exercise

Physical activity increases fluid loss through sweat.

Hydration and Joint Health in India

In India’s hot and humid climate, dehydration is common, especially during summer months.

Outdoor workers, athletes and elderly individuals are particularly vulnerable.

Maintaining adequate hydration supports not only joint health but overall wellbeing.

When to Consult a Doctor

Seek medical advice if you experience:

Persistent joint pain
Swelling
Limited range of motion
Redness or warmth around joints

These may indicate underlying joint disorders requiring evaluation.

Conclusion

Poor hydration can negatively affect joint health by reducing lubrication, increasing stiffness and raising injury risk. Since cartilage and synovial fluid depend heavily on water, maintaining adequate hydration is essential for smooth movement and long-term mobility.

Drinking sufficient water daily is a simple yet powerful step toward protecting joint health. Combined with regular exercise and balanced nutrition, proper hydration supports active and pain-free living.

Small daily hydration habits can make a significant difference in how your joints feel and function.

References

Indian Council of Medical Research – Hydration Guidelines
World Health Organization – Water and Health Resources
Indian Journal of Orthopaedics – Joint Health Studies
National Institute of Nutrition India – Fluid Intake Recommendations
Journal of Sports Medicine – Hydration and Musculoskeletal Health Research

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