Correspondence DOUGLAS W. HUESTIS,Editor Tucson, Arizona
Microscopic Observation in Antiglobulin Procedures
To the Editor: The article entitled “A Survey about Blood Bank Policies and Procedures” in the JulyAugust 1978, issue contained a minor error in the results section. The author states that “most manufacturers of antiglobulin serum require reading reactions macroscopically and microscopically.” After reviewing the product circulars of five of the seven manufacturers, I found the following: “the use of an optical aid is recommended,” “microscopic examination may confirm weak positive reactions,” “negative reactions may be confirmed microscopically” and a statement that the experience of the worker may indicate the use of a microscope. An optical aid may be an agglutination viewer, a magnifying lens or a microscope. The use of a microButch, scope is not “required.”-Suzanne MT(ASCP)SBB, Chief Technologist, Blood Bank, University Hospital, University of Michigan, Ann Arbor, Michigan 48109.
CPD in Canada
To the Editor: Pegels (Transfusion 18:190, 1978) states that CPD blood is presently stored for up to 28 days in Canada. The Canadian Red Cross Blood Transfusion Service, which is the national transfusion service, has never authorized storage of CPD blood for more than 21 days. CPD as a preservative was introduced in 1973; the purpose of this change from ACD was to improve preservation of red blood cells, not to extend the shelflife of whole blood.-B. P . L. Moore, M.D.. D.Sc., Director, National Reference Laboratory, Canadian Red Cross Blood Transfusion Service, 95 Wellesley Street East. Toronto, Ontario, Canada M4Y IH6.
those whose red blood cells fail to react with anti-PI” (citing P. Levine) and the latter? “pp women regularly abort if the fetus receives the father’s PI antigen.” Such assertions may cause unnecessary alarm to p mothers and their physicians. For many years our Unit has been interested in this problem of the offspring of p women and most of our information can be extracted from Tables 26 and 29 of the latest edition of Blood Groups in Man.3 Adding subsequent infomation, the counts are as shown in Table 1. All except one of the 14 P1 x p matings with live children are of European ancestry and six are from Dr. Cedergren’s fine collection around UmeA. The observed 19 P1 and 12 P2 children are therefore close to the numbers expected, 16.7 PI and 14.3 P2. It might be argued that the antibody does not pass the placenta in those families without abortions. Disregarding these families there is nothing to suggest, from the seven children of six Pl fathers, that the P1fetus is at greater risk. The figures in Table 1 suggest, if anything, that P1 may confer protection rather than disaster. We are at a loss to explain the discrepancy between our figures and the American views, but it is obvious that more families of p women need testing for the P blood groups, if their complex role in the cause of abortions is to be better understood.-Ruth Sanger, Ph.D. and Patricia Tippett, Ph.D., MRC Blood Group Table 1. The Groups of the Issue of 2 8 p Women Whose Husbands’ P Groups are Known: Divided for Families with and without Live Children and Abortions’ Live Children Husbands No.
May we use your columns to question sentences in the two papers1B2on the subject of the P system and the offspring of p mothers. The former’ stated “Fetuses which go to term are
Tmafusion Much-April 1979
222
P4
Abortions
PI
8 6 3
16 3 0
8 4 0
0 13 11
P2
1 7 3
0 0 0
2 15 0
0 26 19
Live Children and Abortions of p Mothers
To the Editor:
PI
Adapted from reference 3.
Volume 19 Number 2
Microscopic Observation in Antiglobulin Procedures
To the Editor: The article entitled “A Survey about Blood Bank Policies and Procedures” in the JulyAugust 1978, issue contained a minor error in the results section. The author states that “most manufacturers of antiglobulin serum require reading reactions macroscopically and microscopically.” After reviewing the product circulars of five of the seven manufacturers, I found the following: “the use of an optical aid is recommended,” “microscopic examination may confirm weak positive reactions,” “negative reactions may be confirmed microscopically” and a statement that the experience of the worker may indicate the use of a microscope. An optical aid may be an agglutination viewer, a magnifying lens or a microscope. The use of a microButch, scope is not “required.”-Suzanne MT(ASCP)SBB, Chief Technologist, Blood Bank, University Hospital, University of Michigan, Ann Arbor, Michigan 48109.
CPD in Canada
To the Editor: Pegels (Transfusion 18:190, 1978) states that CPD blood is presently stored for up to 28 days in Canada. The Canadian Red Cross Blood Transfusion Service, which is the national transfusion service, has never authorized storage of CPD blood for more than 21 days. CPD as a preservative was introduced in 1973; the purpose of this change from ACD was to improve preservation of red blood cells, not to extend the shelflife of whole blood.-B. P . L. Moore, M.D.. D.Sc., Director, National Reference Laboratory, Canadian Red Cross Blood Transfusion Service, 95 Wellesley Street East. Toronto, Ontario, Canada M4Y IH6.
those whose red blood cells fail to react with anti-PI” (citing P. Levine) and the latter? “pp women regularly abort if the fetus receives the father’s PI antigen.” Such assertions may cause unnecessary alarm to p mothers and their physicians. For many years our Unit has been interested in this problem of the offspring of p women and most of our information can be extracted from Tables 26 and 29 of the latest edition of Blood Groups in Man.3 Adding subsequent infomation, the counts are as shown in Table 1. All except one of the 14 P1 x p matings with live children are of European ancestry and six are from Dr. Cedergren’s fine collection around UmeA. The observed 19 P1 and 12 P2 children are therefore close to the numbers expected, 16.7 PI and 14.3 P2. It might be argued that the antibody does not pass the placenta in those families without abortions. Disregarding these families there is nothing to suggest, from the seven children of six Pl fathers, that the P1fetus is at greater risk. The figures in Table 1 suggest, if anything, that P1 may confer protection rather than disaster. We are at a loss to explain the discrepancy between our figures and the American views, but it is obvious that more families of p women need testing for the P blood groups, if their complex role in the cause of abortions is to be better understood.-Ruth Sanger, Ph.D. and Patricia Tippett, Ph.D., MRC Blood Group Table 1. The Groups of the Issue of 2 8 p Women Whose Husbands’ P Groups are Known: Divided for Families with and without Live Children and Abortions’ Live Children Husbands No.
May we use your columns to question sentences in the two papers1B2on the subject of the P system and the offspring of p mothers. The former’ stated “Fetuses which go to term are
Tmafusion Much-April 1979
222
P4
Abortions
PI
8 6 3
16 3 0
8 4 0
0 13 11
P2
1 7 3
0 0 0
2 15 0
0 26 19
Live Children and Abortions of p Mothers
To the Editor:
PI
Adapted from reference 3.
Volume 19 Number 2
