Indonesia has confirmed four cases of the 2019 novel coronavirus disease (COVID-19), but concerns remain as to whether tests run by the Health Ministry's laboratory are accurate.

At least five people suspected of having COVID-19 have died since late February before authorities eventually announced two confirmed cases on Monday. Some of the suspected patients died while waiting for their test results, although all of their tests eventually came back negative.

In one case, a health official even admitted to the possibility of flawed results from the test.

Foreign envoys have reportedly questioned the country's testing capabilities, while experts have urged the government to partner with independent laboratories and send samples to other countries as a comparison.

It was only after the country's first confirmed cases that the Health Ministry announced its decision to assign regional labs to test people suspected of carrying the novel coronavirus.

Read also: Indonesia to test more people for COVID-19

Indonesia has tested 227 samples as of Thursday evening, excluding at least 257 people evacuated from cruise ships who are currently quarantined at the Sebaru Island off the coast of Jakarta.

Here are five cases in which patients suspected of having COVID-19 have died across the country, but whose tests reportedly came back negative.

1. Singaporean man in Batam, Riau Islands

The first death was reported in Batam, Riau Islands, where a 61-year-old male Singapore national suspected of having the virus died on Feb. 22 at coronavirus-referral BP Batam Hospital.

The man was initially admitted to Awal Bros Hospital in the city two days earlier. He was eventually referred to the isolation ward of BP Batam Hospital for showing symptoms of COVID-19, such as fever and shortness of breath. He was in Singapore days before being admitted to the hospital.

Batam Port Health Office (KKP) head Achmad Farchanny confirmed to the Post that the patient's samples were sent to Jakarta on Feb. 21 to be tested at the Health Ministry's laboratory. The patient, however, died on Feb. 22, before the lab returned the negative results.

AA, 66, a Singaporean male patient suspected of COVID-19 who died in Batam on Feb. 22 buried in Batam on Wednesday night in a quiet funeral. (JP/Fadli)

The Batam Health Agency soon announced that the Singaporean died of “another illness”. However, the Health Ministry ordered the Riau Islands Health Agency on Monday to observe people who had had contact with the late patient.

Riau Islands Health Agency head Tjeptjep Yudiana said the measures were needed as there was a possibility of flawed results from the test, saying: "There might be errors. We’re only human."

As a result, 33 people in contact with the patient have reportedly been observed and undergone tests, including doctors, nurses, room service staff and drivers, while the patient's wife and two daughters were also monitored.

Read also: Singaporean man earlier suspected of COVID-19 buried in Batam

2. Male patient in Semarang, Central Java

A male patient suspected of COVID-19 died on Feb. 23 at Kariadi Central General Hospital in Semarang, Central Java, after being treated in an isolation room for nearly a week.

The patient reportedly returned to Indonesia on Feb. 12 from Spain via Dubai and presented COVID-19 symptoms after his arrival, including fever, coughing and shortness of breath. He was admitted to the hospital on Feb. 17 and transferred to an isolation room two days later.

Kariadi Hospital doctors said the patient's test results came back negative a day after he was cremated. They said at the time that the patient had died of bronchopneumonia.

Health Minister Terawan Agus Putranto said on Feb. 27 that the man had tested positive for the H1N1 virus, which is a known cause for swine flu.

Terawan said both viruses were similar in terms of symptoms, adding that the patient’s body was treated in accordance with the established protocol to contain H1N1.

Health Minister Terawan Agus Putranto speaks to the press at Sulianti Saroso Infection Hospital (RSPI Sulianti Suroso) isolation building in Jakarta, Monday, March 2, 2020.The Minister of Health stated that two Indonesian citizens were positively affected by the corona virus and were currently in the isolation room of the RSPI Sulianti Saroso. (JP/Seto Wardhana)

3. Male patient in Cianjur, West Java

A 50-year-old male suspected of having COVID-19 died at Dr. Hafiz General Hospital in Cianjur, West Java, on Tuesday, just weeks after his trip to Malaysia.

The man, an employee of state-owned telecommunications company Telkom, had been in Malaysia from Feb. 14 to 17 and started developing symptoms on Feb. 20, according to Cianjur acting regent Herman Suherman.

Herman said the patient was treated at a hospital in Bekasi, West Java, from Feb. 22 to 26 before he went to Cianjur on Feb. 29 for a vacation and to seek the help of a traditional medical practitioner.

In Cianjur, the patient’s health dropped significantly and he was rushed to the isolation room of Dr. Hafiz General Hospital on March 1. The regent said the patient had complained of shortness of breath as well as pain in his lungs and heart.

The Health Ministry's disease control and prevention directorate general secretary, Achmad Yurianto, denied that the patient had died from COVID-19. He added, however, that the ministry would have to ask the hospital first for the patient's actual cause of death.

Telkom issued a statement following the patient’s death, saying that his medical records showed a history of inflammation in his respiratory airways as well as common colds.

Read also: Indonesia launches official protocols for COVID-19 outbreak

4. Patient with COVID-19 contact history in Jakarta

A 65-year-old patient suspected to have contracted COVID-19 died on Thursday at the Sulianti Saroso Infectious Diseases Hospital (RSPI Sulianti Saroso) in Jakarta.

RSPI Sulianti Saroso director Mohammad Syahril said the patient had been in contact with people who came from a country with confirmed COVID-19 cases and was already suffering an underlying medical condition, including high blood pressure, kompas.com reported.

A security personnel walks past in front of the isolation room of Sulianti Saroso Infection Hospital in in Jakarta on Monday. The government has appointed 100 hospitals as referral centers in efforts to prevent the spread of the new coronavirus amid the global outbreak. (JP/Seto Wardhana)

The patient was transferred from a private hospital to RSPI Sulianti Saroso while in deteriorating condition and needed the use of breathing support.

Yurianto said the deceased patient had tested negative for COVID-19 but showed signs of suffering bacterial sepsis from pneumonia.

Read also: Indonesia's first COVID-19 patients recovering, hospital says

5. Patient in Yogyakarta

A 74-year-old patient suspected of having COVID-19 died on Thursday at the Dr. Sardjito General Hospital in Yogyakarta after returning from umrah (minor haj). During the trip, the patient also had a one-night layover in Malaysia.

Antara news agency reported that the patient was transferred from Yogyakarta Regional General Hospital (RSUD Yogyakarta) to Sardjito Hospital’s isolation ward on Monday. The patient suffered from breathing difficulties, coughing and a fever.

The patient died hours before the test results came back negative for COVID-19 and also Middle Eastern Respiratory Syndrome (MERS) on Thursday evening.

The hospital's pulmonologist, Munawar Gani, said that the patient had suffered from pneumonia caused by the klebsiella bacteria. He said the patient had been getting better before he suffered a sudden cardiac arrest, which the patient also had a history of, Antara quoted. (ars)