Dec 04, 2018, 11:01 ET
Inexpensive, Easy-to-Use Test Shows High Accuracy for Sickle Cell Disease Screening
Implementation of a Sickle Cell Disease Screening Initiative in Uganda with HemoTypeSCTM [LBA-3]
A trial in Uganda showed a new test called HemoTypeSCTM was more than 99 percent accurate in detecting sickle cell disease in young children. The test requires only a small drop of blood and returns results in about 10 minutes, making it suitable for routine screening of newborns.
The current gold standard method for sickle cell disease screening is challenging in most low-resource settings due to its cost and requirements for sophisticated equipment and reliable electricity. By contrast, the HemoTypeSC test kit is inexpensive to manufacture (less than $2.00 per test to the end-user), requires no electricity, and can be used without special equipment or training.
Sickle cell disease is an inherited disorder in which an abnormal protein causes red blood cells to malfunction, leading to episodes of severe pain and other serious complications. Although treatments are available to help control the disease, diagnosing sickle cell disease early in life is crucial to patients' ability to benefit from these treatments before permanent damage occurs.
Sickle cell disease is especially prevalent in sub-Saharan Africa. In Uganda, where the trial was conducted, sickle cell disease accounts for about one in five childhood deaths each year.
For the trial, researchers recruited 1,000 children ages one month to about 5 years old at a typical low-resourced Ugandan medical facility. Each participant's blood was tested using two methods: the HemoTypeSC test and hemoglobin electrophoresis, considered the gold standard at this facility. HemoTypeSC diagnostic results matched the results of electrophoresis for 998 out of 1,000 children, an accuracy rate of 99.8 percent.
"The fact that HemoTypeSC is so accurate and so cheap and easy to use shows that this test can be implemented as a widespread newborn screening tool in areas of the world that currently don't screen for sickle cell disease at all, or certainly not in a pervasive fashion," said study author Erik Serrao, PhD, director of business and product development at Silver Lake Research Corporation in Azusa, CA. "If it were to be widely implemented in newborn screening initiatives in sub-Saharan Africa and India, it could significantly reduce the mortality of the disease when combined with both treatment and counseling. This would potentially save millions of lives over several decades."
The HemoTypeSC test works by using highly sensitive and specific monoclonal antibodies to detect hemoglobin proteins associated with sickle cell disease. To use the test kit, health care personnel place a small drop of blood into a paper strip, which is then dipped into a few drops of water within a test tube. A test strip containing the antibodies is then added to the test tube, where it encounters the blood, showing a specific test line if the patient has markers for sickle cell disease.
The trial initially showed conflicting results between HemoTypeSC and electrophoresis for two participants. The HemoTypeSC test indicated the children had sickle cell trait, while hemoglobin electrophoresis indicated they had sickle cell disease. Following up, the researchers discovered that the children had been previously diagnosed with sickle cell disease and had been recently transfused with healthy blood. Because both children had recently received blood transfusions and had both normal and sickle hemoglobin in their blood at the time of testing, the HemoTypeSC test correctly diagnosed these children. The electrophoresis method, with its much lower sensitivity, likely could not detect the transfused normal hemoglobin, which was present at an abnormally low level. After accounting for this discrepancy, the trial was determined to show an accuracy rate of 100 percent for the HemoTypeSC test.
HemoTypeSC is approved for sale in Europe, and according to Silver Lake Research projects that the test will be approved across Africa and in India within the coming year.
The study was sponsored by Silver Lake Research Corporation.