Right tests at right time a challenge | The Daily Star
12:00 AM, August 20, 2019 / LAST MODIFIED: 06:00 PM, August 20, 2019

Right tests at right time a challenge

Say doctors as many patients come late for diagnosis

Jobayer Islam, who had been running a high fever for two days, was taken to Shaheed Suhrawardy Medical College and Hospital on August 14. Doctors there advised that he take an NS1 test, which is done to detect dengue.

The test, however, showed he did not have dengue. 

His parents, residents of the capital’s Shekhertek, took him home, but a day later his condition started deteriorating. His temperature rose, while he also began vomiting and having severe abdominal pain. 

After two days, he was admitted to the same public hospital in critical condition. Doctors there then conducted IgM/ IgG tests -- two antibody tests -- which confirmed the boy had dengue. 

HM Nazmul Ahsan, associate professor at Shaheed Suhrawardy Medical College Hospital, said rapid diagnostic tests, such as NS1 kits, may have lower sensitivity in terms of detection if 72 hours have passed since a fever began. 

He said there were many cases of patients testing negative for dengue initially, but other tests, like complete blood count (CBC) or IgM, later showed the presence of the infection. 

Kankar Ghosh, epidemiologist of Dhaka Shishu Hospital, said around 50 percent of the patients come to hospital after running a fever for three days, which makes the NS1 kits ineffective.


More importantly, the kits have an 82 percent success rate, meaning there is an 18 percent chance of false results, Kankar said.

Three-year-old Ayyad Arham had a high fever of 103 degrees Fahrenheit on August 11. 

He took the NS1 test from a private hospital in Mirpur only 24 hours later, but the test showed that he did not have dengue. 

He then took a CBC test, used to evaluate a person’s overall health and detect a wide range of disorders, including anemia, infection and leukemia. The CBC test conducted on August 13 showed that Ayyad’s platelet count had dropped to 1.35 lakh from the normal range of 1.5 lakh to 4 lakhs.

Sharmin Rahman, mother of Ayyad, said that following the instruction of physicians, they had done IgG and IgM test on August 18, and the IgM tests showed the child had dengue, although his platelet count had increased to 2.56 lakh by then.

The timing of tests is also not the only thing to look out for.

HM Nazmul claimed there were different qualities of NS1 kits and low-quality kits sometimes failed to diagnose dengue. 

Many kits were purchased within a short time following the kit crisis, but they were not all of the same quality, he added. 

He suggested that patients do not depend only on the NS1 kit, but also take IgG/IgM and CBC tests, as some of the main symptoms, such as a falling platelet count, start from the third day of the fever. 

The health expert said they conducted CBC tests on the third or fourth day of the fever, while IgM and IgG tests are done on the sixth or seventh day. 

“If the symptoms seen are of dengue, but NS1 fails to detect the infection, then we keep the patient under observation. We conduct a CBC test on the third or fourth day [of running a fever],” he said.

Technical errors were also issues in getting the correct results, Kankar said.

About technical errors, the medical expert said sometimes lab technicians may make mistakes, which result in the tests coming out negative, adding that it was necessary to see the result of the NSI test within 15 to 45 minutes of taking blood for it. 

“We should not depend on NS1 every time. Rather doctors should look for symptoms of dengue in a patient and then make the final diagnosis,” he said.

Introduced in 2006, the kit allows rapid detection on the first day of fever, before antibodies appear some five or more days later.


Six people died of dengue in Dhaka, Mymensingh, Khulna and Faridpur yesterday, taking the unofficial death toll to 104.

The official death toll, however, is at 40. 

According to the Directorate General of Health Services, 1,615 dengue patients were admitted to different hospitals across the country in the last 24 hours till yesterday 8:00am. 

The number of dengue cases is now 54,797.

Fatema Begum, 45, a resident of Narayanganj’s Bandar upazila, was admitted to the Mitford Hospital in a critical condition and died of dengue at around 1:30am yesterday.

In Mymensingh, Anwar, 40, died of dengue around 1:00am at Mymensingh Medical College and Hospital (MMCH), said Dr AB Md Shamsuzzaman, assistant director of the hospital.

Anwar, from Netrakona’s Kendua upazila, was admitted to the hospital around 4:00pm on Sunday afternoon, the doctor added.

Another person Selim Mia, 27, of the district’s Durgapur upazila, also died of dengue in the same hospital yesterday.

After being diagnosed with dengue in Dhaka, he was admitted to MMCH on August 13 and died yesterday, said Shamsuzzaman, adding that Selim had other health complications as well. 

In Khulna, Mizanur was admitted to Khulna Medical College Hospital with dengue on August 15 and died at 7:00am yesterday, reports UNB quoting Dr Sailendranath Biswas, resident medical officer of the hospital.

In Faridpur, Delwar Hossain died around 10:00am after being diagnosed with dengue at Faridpur Medical College Hospital, UNB reports. 

Delwar’s father Sheikh Safiuddin said they admitted Delwar to Faridpur Sadar Hospital with dengue and shifted him to Faridpur Medical College Hospital on Sunday night.

In another case, Syeda Samiya Aktar, 32, a housewife from Faridpur, died of dengue at a private hospital in Dhaka around 7:30pm on Sunday, said Miraz Hossain, one of Samiya’s cousins. 

(Our Mymenshingh, Faridpur, Bagerhat, Manikganj and Khulna correspondents also contributed to the report.) 

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