Tissue Typing Laboratory

Tissue Typing Test

Tissue typing test, is performed to test the tissue compatibility between the patient (receiver) and the giver (donor) before bone marrow transplantation. The types of human leukocyte antigens, called HLA, are defined with this test. HLA antigens, exist on surfaces of almost all cells in human. Nervous (sunar ? sinir) and immune systems stimulate the foreign antigens that come into the body. HLA antigens have several types, however each person has certain number and types of HLA antigens. Some of them originated from mother ant the others are from father (genetic transition) and it is called "tissue type" or "HLA type". When the tissue transplantation is performed from a person whose HLA type is not similar, to another, the HLA type of donor may be perceived as "foreign" by the patient. In such a case, the immune system of the patient activates in order to destroy the transplanted tissue, thus the "tissue rejection" occurs. Tissue typing test is performed to find the most convenient donor that has the tissue compatibility with patient and to reduce the tissue rejection.

For whom is it applied:

Tissue typing test is performed in our laboratory before the bone marrow transplantations between relatives. It is applied firstly on the siblings, mother, father and children of the patient. If the compatible donor cannot be found, the 3rd and 4th degree relatives may also be scanned.

How is the test performed:

"Tissue Typing Test" is requested by the physician for the patient and his donors. The person who is requested to have test goes to the Blood Collection Unit and gives blood sample. The Sample Admission Section of Tissue Typing Laboratory of Oncology Hospital is applied along with the blood samples. The blood samples are received after the identification control is run. Patient Admittance Form is filled after a file is opened for the patient. The lines of descents and special conditions are recorded.

Tissue typing test is performed with molecular genetics methods. At first, the DNA isolation is practiced with the blood sample. The commercial kits and tests which include PCR-SSP and PCR-SSO methods are performed by using obtained DNA. The test results are analyzed and the report is prepared in compliance with HLA molecular genetics technology. The typing results of HLA-A, HLA-B, HLA-C, HLA-DQ, HLA-DR loci exist in the report.

Consideration for HLA typing analysis

Blood sample that is collected from the arm of the patient is used in tissue typing test. It is necessary to take the blood sample into two tubes with EDTA (purple covered).

The laboratory official should definitely be informed if blood transfusion takes place within last 15 days or if pregnancy is the subject matter. The sample is rejected if label information are not correct or deleted, if samples are clotted, if there are leakage, breakage or cracking on the sample tube, if the samples are not taken into the correct tube and if the information about patient or donor are incomplete (diagnosis of patient, name-surname of the physician who made request, address, etc.).

The results of tissue typing test are reported and submitted within 20 days. Reports are delivered to the physician of the patient inside a sealed envelope.

Since the reports include personal genetic information, they are not recorded into the information management system of hospital. They are protected in the computer of laboratory with passwords, no one, except the authorized laboratory officials can access them.