In developing countries, the donor is sometimes specifically recruited by or for the recipient, typically a family member, and the donation occurs immediately before the transfusion. It is unclear whether applying alcohol swab alone or alcohol swab followed by antiseptic is able to reduce contamination of donors blood. Processing and testing
Donated blood is usually subjected to processing after it is collected, to make it suitable for use in specific patient populations. Collected blood is then separated into blood components by centrifugation: red blood cells, plasma, platelets, albumin protein, clotting factor concentrates, cryoprecipitate, fibrinogen concentrate, and immunoglobulins (antibodies). Red cells, plasma and platelets can also be donated individually via a more complex process called apheresis. The World Health Organization (WHO) recommends that all donated blood be tested for transfusion-transmissible infections. These include HIV, hepatitis B, hepatitis C, Treponema pallidum (syphilis) and, where relevant, other infections that pose a risk to the safety of the blood supply, such as Trypanosoma cruzi (Chagas disease) and Plasmodium species (malaria). According to the WHO, 25 countries are not able to screen all donated blood for one or more of: HIV, hepatitis B, hepatitis C, or syphilis. One of the main reasons for this is because testing kits are not always available. However the prevalence of transfusion-transmitted infections is much higher in low income countries compared to middle and high income countries. All donated blood should also be tested for the ABO blood group system and Rh blood group system to ensure that the patient is receiving compatible blood.
Although more studies are needed, so far, new techniques addressing underlying Eustachian tube dysfunction such as transtympanic dilatation of the Eustachian tube has not been shown to change outcomes of chronic ear surgery. Infections
Recent findings indicate that the keratinizing squamous epithelium of the middle ear could be subjected to human papillomavirus infection. Indeed, DNA belonging to oncogenic HPV16 has been detected in cholesteatoma tissues, thereby underlining that keratinizing squamous epithelia could potentially be a target tissue for HPV infection. Epidemiology
In one study, the number of new cases of cholesteatoma in Iowa was estimated in 1975–76 to be just under one new case per 10,000 citizens per year. Cholesteatoma affects all age groups, from infants through to the elderly. The peak incidence occurs in the second decade. See also
Chronic suppurative otitis media
Otic polyp
Endoscopic ear surgery

References
External links

Information on Cholesteatomas
Laser Cholesteatoma Surgery