Diagnosing Hemoglobinopathies

The evolution of the clinical laboratory industry has seen a lot of progression, both to the technology available to laboratorians and the changing SOPs being put into practice. In hematology departments, the different specialties are using new techniques in the examination of specimens, looking for more specialized signs and bio-markers. In a recent interview with ADVANCE, Trefor Higgins, MSc, FCACB, director of clinical biochemistry at DynaLife Dx, discussed the analysis and diagnosis of hemoglobinopathies and thalassemais.

“It’s no longer just doing a simple test, look for S and you will be alright,” explained Higgins. “Now, it’s become a whole sophisticated branch that requires substantial expertise to interpret.”

Despite being two distinct diseases, thalassemias and hemoglobinopthies are usually grouped together. The major difference between the two is a decrease versus a disruption. According to Higgins, thalassemaias are the result of a deficiency in one of the globin chains within the hemoglobin, which causes a problems in terms of production. With hemoglobinopathies, on the other hand, the problem the hemoglobin is interrupted by the removal or substitution of an amino acid. Each type of disease is characterized by anemia or another blood disorder that presents in such a way that it can sometimes mimic other diseases.

“Thalassemias arise from a deficiency in production of one of the globin chains that make up hemoglobin,” said Higgins. “So, it’s a decrease in production and it’s a quantitative change On the other hand when one of the amino acids that make up the chain – the globin chain – is substituted or removed a qualitative change happens which is a hemoglobinopathy.”

While thalassemais and hemoglobinopathies are typically discovered through clinical investigation, they can also simply be the result of a unexpected finding. During his interview, Higgins described his “happy story,” in which a patient was assumed to be diabetic, but when additional testing was ordered because of his abnormal A1c and glucose levels, a hemoglobinopathy was found instead. Originally, laboratorians relied on methods like electrophoresis to identify the diseases, but due to the introduction of breakthrough technologies like genetic assays, there are currently several effective techniques. In Higgins’ laboratory, for example, they utilize HPLC.

“We call it a hemoglobinopathy-thalassemia investigation. In that, we use a technique that determines if there are some abnormal hemoglobins present or hemoglobinopathies, and also gives us a quantitative measurement of hemoglobin F, hemoglobin A2 – because that’s important to differentiate between alpha-thalassemia and beta-thalassemia,” continued Higgins. “So, the techniques to be used are primary HPLC or capillary electrophoresis to determine the hemoglobinopathy or thalassemia.”

Thalassemias and hemoglobinopathies vary by type, location and severity. Patients with simple traits of the diseases can experience little to no symptoms or complications as a result, but depending on each disease specifically, they can also be very dangerous to the patient. For example, alpha- and beta-thalassemia traits are characterized by smaller cells, but the body makes up for this by producing a lot of them. On the other end of the spectrum are alpha- and beta- thalassemia major , each of which are life-threatening if not discovered and treated. Alpha-thalassemia major, or hemoglobin Bart’s, usually affects women at around 26 weeks of pregnancy, while beta-thalassemia major, or Cooley’s anemia is usually seen in infants aged between 30 days and six months and must be treated with hydroxyurea.

“We’ve gone from a benign condition with alpha- and beta-thalassemia trait to a life-threatening condition called hemoglobin Bart or Cooley’s anemia, which requires life-long therapy,” said Higgins. “So, the diseases of thalassemias range from relatively benign all the way through to serious and life-threatening.”

There are a number of confirmatory tests available for both hemoglobinopathies and thalassemias. Common disorders like sickle cell disease are caused by hemoglobin S, which is tested for with relative ease, but there are also hemoglobin variants that are unknown to the laboratory professionals. In these cases, confirmatory testing is required and the specimen is sent out for a definitive analysis. For thalassemias, including beta-thalassemia, the laboratory must test to measure hemoglobin A2 accurately, but alpha-thalassemias require more complex approaches like molecular diagnostic techniques.

Depending on the size of the facility, hemoglobinopathy and thalassemia testing can fall into multiple areas of the laboratory – from the main laboratory to the hematology division to the chemistry division (as is the case in Higgins’ laboratory). Although these have largely been regarded as simple assays with easily interpreted results, Higgins also noted the growth of this kind of testing into a specialized and sophisticated branch. As such, the healthcare industry can expect to see hemoglobinopathy and thalassemia testing expand into its own department rather than being houses in various departments.

Michael Jones is on staff at ADVANCE.

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