World Thrombosis Day - how dangerous can blood clots be and why early detection is crucial
Thrombosis Day, Transasia Bio-Medicals sheds
some light on the prevalence of VTE and its detection by a simple blood test
such as D Dimer.
Blood clots - the
first line of defense or a cause of concern?
Blood clotting or coagulation is the body’s defense tactic against
bleeding. In the case of an injury, the clotting system is activated to ‘plug’
the injury site and prevent excess blood loss. Once healed, the body breaks
down the clot. In certain instances, the blood clot may fail to dissolve after
an injury, or clots may form inappropriately, within a blood vessel, preventing
normal flow. This process is called thrombosis.
Know the different
types
Broadly speaking there are two main types - venous and arterial, depending on where the clot occurs. Arterial thrombosis can result in heart attacks and strokes. On the other hand, in venous thrombosis (VTE), clots form mainly in the deep veins. It includes both Deep Vein Thrombosis (DVT), formation of clots usually in the deep veins of the legs and Pulmonary Embolism (PE), a condition in which the blood clots travel and get lodged in the lungs.
VTE- a significant healthcare burden
VTE is a common and potentially life-threatening condition affecting hospitalized and non-hospitalized patients. A global health concern, it is often overlooked, recurs frequently and results in long-term complications. It contributes substantially to patient morbidity, mortality and cost of management.
The true incidence of VTE is hard to estimate. Having said that, risk of VTE is especially high in hospitalized patients, especially in the immediate post-operative period, immobility being the major reason. In fact, 60% of VTE cases occur during or following hospitalization. (1)
India perspective
Due to increased awareness and early diagnosis, the incidence of VTE is rising, contrary to earlier belief that it is low in Asia and India.
A study spanning 19 Asian countries revealed that DVT occurred in 41% of patients undergoing major hip joint surgery without thrombo-prophylaxis.(2)
· In another global epidemiological study consisting of 68,183 patients including 2,058 from India, 54% of hospitalized (45% medical and 61% surgical) patients had risk factor for VTE. (2)
Testing scenario in India
In a majority of cases, VTE is clinically silent and can easily exist without any warning symptoms. This poses a challenge for clinical diagnosis, often being misdiagnosed with another condition. DVT can progress to PE within a short span of time and prove to be fatal. Thus, people at risk should be under regular diagnostic screening.
D Dimer testing is of clinical use when there is a suspicion of VTE and is nowadays a commonly referred test. It is an early, sensitive marker for DVT, PE and coronary artery disease. D Dimer is a small protein fragment, left floating in the blood, on clot degradation. Normally it would go away with time. However, its presence in high levels in the blood is indicative of major clots.
A negative result rules out thrombosis, therefore, D Dimer is used by medical experts to definitely rule out thromboembolic diseases, especially where the probability is low.
Different D Dimer
assays
There are multiple technologies available for D Dimer testing. However, not all are specific, sensitive, quantitative and at the same time affordable. Another limitation is that these kits are often available in large pack sizes, with reagents of limited expiry. As a result, a lot of labs, with a small workload and manual systems do not perform these tests.
Enzyme-linked immunosorbent assay (ELISA), chemiluminescence immunoassay (CLIA), immunofluorescence assay (IFA), point-of-care testing and immunoturbidimetric assay are various methods for D Dimer detection.
Choosing the right D
Dimer assays
Of all, the latex-enhanced immunoturbidimetry assay performed is the most commonly used technology. This quantitative method is preferred for being faster, with higher sensitivity and specificity and easy to process on fully automated coagulation analyzers.
The type and size of latex and wavelength of light, at which it is measured, are important factors. A small particle would not work well at long wavelengths, whereas a large particle would behave poorly at shorter wavelengths. Most of the smaller semi-automated analyzers have a short wavelength as the only option.
“At low wavelength, the absorbance of interfering substances such as, hemoglobin, bilirubin and lipids is high, leading to variances in reporting. Hence it is important to choose a D Dimer assay that operates at higher wavelengths”, concedes Dr. Swarupa Bhagwat, Asst. Professor, Transfusion Medicine, Seth GS Medical College and KEM Hospital, Mumbai.
COVID-19 and
thrombosis
Global studies have indicated the prevalence of DVT in hospitalized COVID-19 patients is 14-28%, particularly high in patients with diabetes(3). In fact, immobility and restricted activity during the course of treatment leads to an increase in the prevalence of PE. There is also a disturbing trend, that patients who have recovered from COVID-19 are going back to hospitals with breathing problems due to lung damage caused by PE.
There have also been incidences of blood clotting post COVID-19 immunization, reported globally. According to the National Adverse Effects Following Immunization Committee, Indians are at a very minuscule but definitive risk of thromboembolic events. The data analyzed by the committee suggests that South Asians may genetically have less propensity to develop thrombosis post-vaccination as compared with those in western countries.
Transasia
Bio-Medicals offers Erba D Dimer kit
Transasia's Erba D-Dimer R test kit aids in determining the change in D Dimer concentration, as an early indicator for exclusion of DVT and PE. It is a high quality immunoturbidimetric assay that is pre-programmed and can easily be performed on Transasia’s ECL series analysers.
Sources
1. https://www.worldthrombosisday.org/
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6600090/
3. https://indianexpress.com/article/india/covid-lung-disease-blood-clots-experts-research-7306787/
Comments
Post a Comment