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

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

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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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Vitamin D

Vitamin D Deficiency Symptoms: Signs Your Body May Be Lacking Vitamin D

Vitamin D is an essential nutrient that plays a vital role in maintaining strong bones, supporting the immune system and regulating several important functions in the body. Despite its importance, vitamin D deficiency is one of the most common nutritional deficiencies worldwide.

In India, vitamin D deficiency has become increasingly prevalent due to lifestyle factors such as limited sunlight exposure, indoor working environments and dietary habits. According to the Indian Council of Medical Research (ICMR), a significant percentage of the population may have insufficient vitamin D levels.

Recognizing the symptoms of vitamin D deficiency early is important because prolonged deficiency can lead to serious health complications affecting bones, muscles and overall wellbeing.

What Is Vitamin D and Why Is It Important?

Vitamin D is often called the “sunshine vitamin” because the body produces it when the skin is exposed to sunlight. It plays a key role in calcium absorption, which is essential for maintaining healthy bones and teeth.

In addition to bone health, vitamin D supports several important functions including:

immune system regulation
muscle function
inflammation control
hormonal balance

Low levels of vitamin D can disrupt these functions and contribute to various health problems.

Common Symptoms of Vitamin D Deficiency

Vitamin D deficiency can manifest through several symptoms, many of which are often overlooked or mistaken for other health issues.

Persistent Fatigue

Constant tiredness or low energy levels may be one of the earliest signs of vitamin D deficiency. Even after adequate rest, individuals with low vitamin D levels may continue to feel exhausted.

Vitamin D plays a role in cellular energy production, and insufficient levels may contribute to chronic fatigue.

Bone and Back Pain

One of the most well-known effects of vitamin D deficiency is bone discomfort. Vitamin D helps the body absorb calcium, which is essential for maintaining bone strength.

Low vitamin D levels may cause:

bone pain
lower back pain
increased risk of fractures

Persistent bone discomfort should be evaluated by a healthcare professional.

Muscle Weakness

Vitamin D is important for muscle health and function. Deficiency can lead to muscle weakness, cramps or general muscle fatigue.

Older adults with vitamin D deficiency may also experience reduced mobility and increased risk of falls.

Frequent Illness or Infections

Vitamin D plays a key role in supporting the immune system. Individuals with low vitamin D levels may experience frequent colds, infections or slower recovery from illness.

Research suggests that adequate vitamin D levels help strengthen immune defenses against respiratory infections.

Mood Changes and Depression

Vitamin D may influence brain function and mood regulation. Some studies have found a connection between low vitamin D levels and mood disorders such as depression or anxiety.

People experiencing persistent mood changes should consider evaluating vitamin levels as part of a broader health assessment.

Hair Loss

Severe vitamin D deficiency may contribute to hair thinning or hair loss. While hair loss can have multiple causes, nutritional deficiencies including vitamin D deficiency may play a role.

Slow Wound Healing

Vitamin D contributes to the body’s inflammatory response and tissue repair processes. Individuals with deficiency may notice slower wound healing or delayed recovery from injuries.

Who Is at Risk of Vitamin D Deficiency?

Several factors can increase the risk of vitamin D deficiency.

Limited Sun Exposure

People who spend most of their time indoors or use strong sun protection regularly may not receive enough sunlight to produce sufficient vitamin D.

Urban lifestyles and indoor work environments contribute to this problem.

Older Adults

As people age, the skin becomes less efficient at producing vitamin D from sunlight. Older adults may therefore require additional dietary intake or supplements.

Individuals with Darker Skin

Melanin reduces the skin’s ability to produce vitamin D from sunlight. Individuals with darker skin tones may require longer sun exposure to produce adequate levels.

Poor Dietary Intake

Few foods naturally contain vitamin D. Diets lacking fortified foods, dairy products or fatty fish may contribute to deficiency.

Medical Conditions

Certain medical conditions such as kidney disease, liver disease or digestive disorders can affect vitamin D absorption and metabolism.

How Is Vitamin D Deficiency Diagnosed?

Vitamin D deficiency is diagnosed through a simple blood test that measures the level of 25-hydroxyvitamin D in the bloodstream.

Doctors may recommend testing for individuals who experience symptoms of deficiency or belong to high-risk groups.

Early diagnosis allows healthcare providers to recommend appropriate treatment and lifestyle adjustments.

How to Improve Vitamin D Levels

Sunlight Exposure

Regular sunlight exposure is one of the most effective ways to increase vitamin D levels. Experts generally recommend 10 to 30 minutes of sunlight exposure several times per week, depending on skin type and location.

Dietary Sources of Vitamin D

Although limited, certain foods contain vitamin D, including:

fatty fish such as salmon and mackerel
egg yolks
fortified milk and cereals
mushrooms

Including these foods in the diet can help maintain healthy vitamin D levels.

Vitamin D Supplements

In cases of significant deficiency, doctors may recommend vitamin D supplements. The dosage depends on the individual’s vitamin levels, age and health status.

It is important to take supplements under medical supervision to avoid excessive intake.

Preventing Vitamin D Deficiency

Maintaining adequate vitamin D levels requires a balanced combination of sunlight exposure, proper nutrition and regular health monitoring.

Routine health checkups and vitamin testing can help identify deficiencies early and prevent complications.

Adopting a healthy lifestyle with balanced nutrition and outdoor activity can significantly improve vitamin D status and overall health.

Conclusion

Vitamin D deficiency is a common but often overlooked health concern. Symptoms such as fatigue, bone pain, muscle weakness and frequent infections may indicate low vitamin D levels.

Early detection and proper management are essential to prevent long-term health complications. By ensuring adequate sunlight exposure, maintaining a balanced diet and undergoing regular health checkups, individuals can support healthy vitamin D levels and improve overall wellbeing.

Recognizing the warning signs of vitamin D deficiency and seeking timely medical advice can help protect long-term health and maintain optimal body function.

References

  • Indian Council of Medical Research (ICMR) – Nutritional Deficiency Reports

  • World Health Organization (WHO) – Micronutrient Deficiency Guidelines

  • National Institute of Nutrition (NIN) India – Vitamin D Research Reports

  • Lancet Public Health – Nutritional Health Studies

  • National Institutes of Health (NIH) – Vitamin D Fact Sheets for Health Professionals

See all

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