I refer to the letter from Bharat Alva, headlined, 'Angered by donor snub' (South China Morning Post, August 2). In accordance with international practice all prospective blood donors are screened by the Blood Transfusion Service (BTS) to determine suitability under established donor selection criteria before they are accepted as donors. This is done for their own protection as well as patients. The questions which your correspondent and his colleagues were asked are standard questions under the existing donor selection cri-teria. It is also clearly stated in the blood donor health inquiry form which is given to all prospective donors to read that anyone who has travelled abroad the previous 12 months or resided in Hong Kong for less than three years should inform the BTS nurses. Interviews to determine an individual's suitability to give blood are usually carried out on a one-to-one basis in private. In view of the long queue in the incident quoted by your correspondent, the nurse thought it would help save time in case there was anyone in the waiting queue who was not likely to meet the residential/travelling criteria. I should like to take the opportunity to apologise to Bharat Alva and his colleagues for any inadvertent offence caused as a result of over-enthusiasm on the part of the nurse on this occasion and assure him that the BTS does not practise any discrimina-tion. I hope the misunderstanding would not deter Bharat Alva from giving blood as the BTS depends on public spirited persons like him to ensure that the demand of blood in Hong Kong is fully met at all times. J.W. GOODAIR for Hospital Chief Executive Hong Kong Red Cross Blood Transfusion Service