1. The effect of Nucleic acid testing (NAT) in the safety of blood transfusions
F. Kourgia, M. Vini, E. Zervou
Blood Centre of University Hospital of Ioannina, Ioannina, Greece

2. Around the world, more than 92 million blood donations are collected every year.
 From these, a single whole-blood donation can be transfused in up to three people, while blood-derived products from a single donation may be given to hundreds of patients.
Laboratory screening of donated blood and blood products for infectious diseases is a key safety measure in protecting patients and preventing the spread of serious diseases.

3. In accordance with guidelines, the minimum requirements of blood testing include syphilis, HBV, HCV and HIV. In Greece HTLVI/II also is tested.
The norm for viral testing has been serology, but increasingly NAT is been implemented where resources allow.
NAT is a molecular technique used to detect a virus or a bacterium
NAT improves the safety of transfusions because :
-shortens the serological silent window period  a time between when the donors have been infected and when they show up as positive by antibody or antigen tests and also
-detects the cases of occult HBV (HbsAg -/anti-Hbc+)

4. HCV 4

5. HBV 5

6. HIV 6

7. Aim:
To determine the NAT yield ( the infectious agent is not serologically detected but only by NAT) for HBV, HCV and HIV in the blood donations which conducted in the Blood Centre of University Hospital of Ioannina.

8. Methods: :
donations ( for whole blood and for platelets apheresis ) were tested
For serological testing Abbott and Ortho assays were used.
For individual (ID) NAT testing the Procleix Ultrio (Novartis) until the end of 2013 and after this time the Cobas AmpliPrep (Roche) were used.

9. Results: In this period: 1 case of HIV in the window period
17 cases of occult hepatitis B and
11 cases of possible occult hepatitis B (NAT initially reactive, anti-HBc positive but the repetition of NAT was negative, probably due to a low viral load) were identified.

10. Conclusion:
The implementation of NAT detects infectious donations that could be missed by serological testing and so plays an important role in the safety of blood transfusions.
In our center we found that the HBV NAT yield was 1/2.329 (1/3.836 clear occult HBV and 1/5.929 possible cases ) and the HIV NAT yield was 1/ blood donations.

11. National data (SKAE) 2007-2013:
ΝΑΤ yield in 3,240,394 blood donations
Only NAT positive
8 HIV /405049
19 HCV /70547
436 HBV /7432

12. Thank you