Dummies Guide to D-dimer Test for Corona Virus

My COVID-19 Assignment

These days, every other day, I hear someone in my close contacts catching coronavirus. But the one person my family is particularly scared of catching coronavirus is my Aunt. Not because she is 63 years old. That way my uncle is 65 years old. But because my aunt Vanitaben is a maniac. Ever since our PM announced about Corona Virus and advised not to step out of the house, I feel she is the only person who has taken our PM’s advice so seriously. They live in a big Bungalow with a lawn on the front side. But it will be now six months since their neighbours saw her on the lawn. She is so frightened of the coronavirus that she strictly follows social distancing at all times, even with her son, who has to go out frequently for office work. We all knew that if Vanitaben catches corona, then we all will have a tough time convincing her. But as per Murphy’s law.

“Anything that can go wrong, will go wrong.” 

That day I was returning from office when my cousin called me,

“Bro, we are in mess. Mom had a mild cough and body ache. So the doctor asked her to carry out Corona test. And guess what, my Mom doesn’t need a laboratory report to prove that she is COVID positive. The reports will come tomorrow, but today itself she has locked herself into a room and is not seeing anyone. Please do something, dear.”  

Being the most respected fellow in the house, I am often tasked with such heavy-duty assignments. I knew the task was tough. But I remembered the dialogue from Chhichhore movie,

“Hum try karenge, aur kar bhi kya sakte he!” (We will try, what else can we do!).

So after finishing my dinner, I called my aunt and asked her,

“Why are you so afraid of Coronavirus? Did you know that Amitabh Bachan recovered from Corona?” 

“He will, of course, he gets 5-star treatment. Who will give me such treatment?” she said.

“Oh common, you are not going to die. Your report has also not yet come. Then why worry? You know Amit Shah also recovered, despite being diabetic.” I tried to convince her.

“Oh common, he too gets 5-star treatment,” she said.

So now I went one step further, “Do you know 113-year-old lady, Maria Branyas from Spain recovered from COVID-19?”

“Off-course she will survive, she was in Spain, where health infrastructure is so good, but I am in India,” she said.

So far I did not have any success. So I put on my next argument, “Do you know 93-year-old Thomas Abraham and 88-year-old Mariayamma recovered from Covid-19 after days of life-and-death battle in Medical College Hospital in Kottayam, Kerala. Further, do you know 94-year-old Lal Mohan Seth from Calcutta defeated Covid-19?”

“These Bengali and Keraliyan People eat lots of non-veg items, that’s why they are so strong. I eat only Dal Chaval, how will I get through this corona?”, she said. She seemed to have every counter argument for my arguments.

But I had no choice but to continue. So I said, “OK then did you know that 94-year-old P. Vijayalakshmi from Hyderabad did not even have any critical symptoms of corona and she defeated Covid-19 easily.”  

“Yes, exactly, if a person is asymptomatic, then there is nothing to worry about. But how can we know whether we will be asymptomatic or critically ill?”

She was testing my patience, but I could not afford to lose, so I continued, “Ok then how about 105-year-old Mohanamma from Kurnool, Andrapradesh who had comorbid conditions and still defeated Corona. At 105, she lives a simple life with a balanced diet, meditation, yoga and regular walk.”

“True Yoga definitely boosts immunity, but the last time I practised yoga was 10 years ago when I had attended Baba Ramdev’s Yog shibir. I have never practised Yoga thereafter. I wished I had continued to practise, then I too would have been much more confident against Corona. But now it’s too late. In case I die, please take care of my son.” she said with tears in her eyes. 

This was an emotional moment forced upon me, and for a moment I felt like giving up. But soon, I remembered that I must not be fooled by her arguments, and so I regained my confidence and bounced back,

“Just stop talking such nonsense. Nothing is going to happen to you. You are a healthy woman. If 103-year-old Sukha Singh Chhabra, from Thane, Maharashtra, can come out of ICU, so can you. If 110-year-old Hamidhabi from Ambur, Tamilnadu can survive through this coronavirus, so can you. If 105-year-old Asma Beevi from Kollam, Kerela can defeat Coronavirus after fighting for over three months-long battle, so can you. If 106-year-old Mukhtiar Ahmed from Delhi can defeat Corona Virus, so can you. If a 105-year-old Afghan woman Rabia Ahmed suffering from Alzheimer’s with dementia (पागलपन), can get cured in Greater Noida’s Sharda hospital, so can you. Don’t let age or any chronic disease decide your fate against corona.  You can defeat corona, irrespective of your age and comorbidity! So please give up on such depressive thoughts and fight back to normal.”

“We will see,” she said.

The next day, as I was travelling to my office, I again received a call from my cousin, “Brother, out of tension, Mom did not sleep last night.  But this morning the reports came. Its nothing, Mom’s COVID report is negative, its just seasonal flu!”

On hearing this, I was finally relieved and my Covid-19 task was completed!

Blood Clots in COVID 19 Patients

Well, no matter how much satire is used to lighten the subject of Covid-19 virus, things are scary. Thousands of people have succumbed to death because of Pandemic. With no cure on hand, the German federal state of Hamburg mandated to carry out Autopsies for patients dying with a polymerase chain reaction. Though the sample size of this study was small (12 patients), the results were quite shocking.

The autopsy revealed deep venous thrombosis in 7 of 12 patients (58%) in whom venous thromboembolism was not suspected before death. Also, the pulmonary embolism was the direct cause of death in 4 patients. Postmortem further revealed that 8 patients suffered from histomorphologically diffused alveolar damage. In all patients, SARS-CoV-2 RNA was detected in the lung at high concentrations; viremia in 6 of 10 and 5 of 12 patients showed high viral RNA titers in the liver, kidney, or heart.

Now if you are not a medical expert like me, then let me put it in simple words. The study revealed that critically ill patients were at high risk of developing blood clots, which can cause kidney failure, blood clots in veins, leading to several other associated complications like stroke. Hence the researchers have emphasised on the need for early screening for detecting blood clots in COVID-19 patients.

What is D-dimer?

Whenever there is an injury in our body, blood leaks from our body. To prevent the loss of blood, our body secretes a protein known as Fibrin. Just like a fishnet is formed by cross-linking nylon threads, this Fibrin threads cross-link with each other to form a fibrin net. This Fibrin net then combines with Platelets to create blood clots, which moves to the injury site and stops the flow of blood. This process is called Hemostasis.

After some time, when the injury is healed, there is no longer requirement for the blood clot. So now our body secretes another enzyme known as Plasmin, which breaks the blood clots into smaller pieces of cross-linked fibrin. Then this fibrin is further broken into D-dimer.

D-dimer test measures the amount of this D-dimer in the blood. So when a patient is suffering from COVID-19, because of unknown reasons, blood clots are formed in the blood. Subsequently, our body then secretes Plasmin to break these blood clots. Usually, this is an automated process, and the patient is not aware of these processes inside the body. However, the problem starts when the COVID-19 Virus forms excessive blood clots in the blood. In this condition, as there is no external injury, the clots of blood circulation in our venous system and can get trapped at narrow pathways. This can lead to serious conditions like kidney failure, stroke, etc. So as this knowledge of blood clots became evident, a lot of Doctors are now relying on continuously measuring these D-dimer levels for Corona positive patients.

D-dimer test

Simply speaking, D-dimer test is a blood test which helps in monitoring the blood clots. A positive test outcome means that the D-dimer level in the body is higher than normal and suggests the possibility of having blood clots.
“The COVID-19 pandemic is opening doors for multidisciplinary collaboration so trauma acute care surgeons and intensivist can bring the tools they use in their day-to-day lives and apply them in the critical care setting to new problems,” said Franklin Wright, Assistant Professor of Surgery at the University of the Colorado School of Medicine in the US.

The researchers tested outcomes for all patients who had a TEG assay as part of their treatment for COVID-19 infection and other conventional coagulation assays, including ones that measure D-dimer levels.

In another study submitted to the Journal of the American College of Surgeons, data of 44 patients treated for COVID-19 infection between March 22, 2020, and April 20, 2020, were analysed. The study found that 80% of patients with both positive D-dimer test findings were placed on dialysis compared with 14% who tested for a negative finding. Further, it was reported that the patients with affirmative test findings also had a 50% rate of venous blood clots compared with 0% for those patients with negative finding. Figure -1 shows Correlations of D-dimer levels with clinical staging for different patients. As seen from this figure, the D-dimer levels of critically ill patients were found to be severely high. 

Figure-1: Correlations of D-dimer levels with clinical staging (Courtesy: https://jintensivecare.biomedcentral.com/articles/10.1186/s40560-020-00466-z)

Figure -2 shows the Correlations of D-dimer levels with in-hospital mortality. Again, here the non-survivors had higher D-dimer levels. 

Figure-2: Correlations of D-dimer levels with in-hospital mortality. (Courtesy: https://jintensivecare.biomedcentral.com/articles/10.1186/s40560-020-00466-z)

Treatment

If the D-dimer tests reveals higher D-dimer levels in COVID-19 patients, Doctors can treat the patients with medicines or injections which help in avoiding blood clots within body. The type of medicine is based on patients health conditions and varies from patient to patients. Self medication in such cases must be strictly avoided. 

Conclusion

Different research findings have reported that there is a correlation in D-dimer levels in COVID-19 patients. Researchers have suggested that early blood clot detection can be vital in saving a patient’s life. This can facilitate the doctors in giving early treatment for avoiding complications, which can lead to a speedy recovery. So next time if you find someone is COVID-19 positive, definitely insist on D-dimer testing along with measuring oxygen levels and temperature for avoiding mortality. We all know of the proverb,

“Prevention is better than cure.”

But for COVID-19 patients,

“Early detection, is the best way to cure”

JITEN H. BHATT

References:

Wichmann D, Sperhake J-P, Lütgehetmann M, Steurer S, Edler C, Heinemann A, et al. Autopsy Findings and Venous Thromboembolism in Patients With COVID-19: A Prospective Cohort Study. Ann Intern Med [Internet]. 2020 [cited 2020 May 12]; Available on: https://annals.org/aim/fullarticle/2765934/autopsy-findings-venous-thromboembolism-patients-covid-19-prospective-cohort-study

Yao, Y., Cao, J., Wang, Q. et al. D-dimer as a biomarker for disease severity and mortality in COVID-19 patients: a case control study. j intensive care 8, 49 (2020). https://doi.org/10.1186/s40560-020-00466-z

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