Identification of RHD allelic variants discovered by atypical typing results on the NEO/Echo platforms.

Some individuals are at risk of anti-D alloimmunization if they inherit D antigens that are qualitatively and/or quantitatively different than wild-type D. We hypothesized that patients who showed serologically inconsistent, weak, or historically discordant D typing results by microplate direct agglutination (MDA) on NEO or Echo (Immucor, Norcross, GA) might be at risk of carrying RHD allelic variants. The present study was designed to evaluate patients with RHD allelic variants if they presented with weakly reactive D typing results on the NEO or Echo. Patients were selected for RHD genotyping if their specimens showed weak reactivity with either series 4 or series 5 anti-D typing reagent, if the strength of reactivity was ≤1+ on the NEO or Echo, or if historical or current D typing results were discordant with current results. Patients selected for RHD genotyping were also tested by saline tube testing using the same anti-D series 4 and 5 reagents. Genotyping was performed by the Immucor genotyping laboratory in Warren, NJ. Of 80 patients whose samples met study inclusion, 52 (65.0%) were found to have RHD allelic variants. Sixteen patients (20.0%) expressed possible Ceppellini effect reactivity. Most importantly, 51.25 percent of the patients who presented with weakly reactive D typing results by MDA testing on the NEO (≤1+) or Echo (≤1+) had RHD allelic variants that were associated with the potential for anti-D alloimmunization. Laboratories that use MDA testing on the Neo or Echo for D typing should consider that female patients of childbearing age might be at risk of anti-D alloimmunization if they are classified as D+ based on weakly reactive D typing results.Some individuals are at risk of anti-D alloimmunization if they inherit D antigens that are qualitatively and/or quantitatively different than wild-type D. We hypothesized that patients who showed serologically inconsistent, weak, or historically discordant D typing results by microplate direct agglutination (MDA) on NEO or Echo (Immucor, Norcross, GA) might be at risk of carrying RHD allelic variants. The present study was designed to evaluate patients with RHD allelic variants if they presented with weakly reactive D typing results on the NEO or Echo. Patients were selected for RHD genotyping if their specimens showed weak reactivity with either series 4 or series 5 anti-D typing reagent, if the strength of reactivity was ≤1+ on the NEO or Echo, or if historical or current D typing results were discordant with current results. Patients selected for RHD genotyping were also tested by saline tube testing using the same anti-D series 4 and 5 reagents. Genotyping was performed by the Immucor genotyping laboratory in Warren, NJ. Of 80 patients whose samples met study inclusion, 52 (65.0%) were found to have RHD allelic variants. Sixteen patients (20.0%) expressed possible Ceppellini effect reactivity. Most importantly, 51.25 percent of the patients who presented with weakly reactive D typing results by MDA testing on the NEO (≤1+) or Echo (≤1+) had RHD allelic variants that were associated with the potential for anti-D alloimmunization. Laboratories that use MDA testing on the Neo or Echo for D typing should consider that female patients of childbearing age might be at risk of anti-D alloimmunization if they are classified as D+ based on weakly reactive D typing results.

Major non-ABO incompatibility caused by anti-Jk(a) in a patient before allogeneic hematopoietic stem cell transplantation.

A 49-year-old white man with blood group AB, D+ was found to have alloanti-Jk(a) and -K when he developed a delayed hemolytic transfusion reaction before allogeneic hematopoietic stem cell transplant (HSCT). Given that his stem cell donor was blood group O, D+, Jk(a+), K-, rituximab was added to his conditioning regimen of fludarabine and melphalan to prevent hemolysis of engrafting Jk(a+) donor red blood cells. The patient proceeded to receive a peripheral blood stem cell transplant from a matched unrelated donor with no adverse events. To our knowledge, this is the first case of successful management of major non-ABO incompatibility caused by anti-Jk(a) in a patient receiving an allogeneic HSCT reported in the literature.

Transfusion practice in medical patients.

OBJECTIVE: Blood transfusion raises serious issues of safety and economics. We therefore examined blood usage and its characteristics in medical inpatients, given the relative scarcity of existing data. DESIGN: During a 1-year period, transfusion episodes on two medical services were reviewed by five specialists for justifiability on the basis of generally agreed on guidelines. SETTING: The study was conducted at two institutions, a municipal teaching hospital where house staff deliver care and a community hospital where patients are under the direct care of private physicians. PATIENTS: Four hundred thirty-eight randomly selected transfusion episodes on the medical services of the two institutions were reviewed. MAIN OUTCOME MEASURES: The prevalence of unjustifiable transfusions based only on the information available to the managing physician at the time of transfusion. RESULTS: Eighteen percent of the 438 randomly selected transfusion episodes were viewed as not justifiable by at least four of five reviewers; another 17% were classified as equivocal because two or three reviewers judged them to be not justifiable. The most striking observation was the greater prevalence of nonjustifiable transfusion episodes at the community hospital (26% vs 16% at the teaching institution; P = .0121). Other observations included a tendency for physicians to prescribe transfusions by the numbers (at least 11% of nonjustifiable transfusions) and to overtransfuse. The routineness with which transfusion was viewed by managing physicians was also identifiable by the absence of written transfusion notes in 39% of all episodes reviewed, which incidentally raises questions about the adequacy of the medical chart's documentary functions today. CONCLUSIONS: The rate of nonjustifiable or equivocal transfusion on medical services may be as high as 35%. Reliance on numbers rather than clinical status seems to be a major problem. Education is obviously a critical issue and should also target private practitioners, who seemed to perform less well than physicians in training. Transfusion guidelines that use specific hematocrit values also need to be reexamined.

Different HLA haplotypes in Mexican Americans with IDDM.

The study of HLA histocompatibility antigens and insulin-dependent diabetes mellitus (IDDM) in non-White populations may provide a unique opportunity to more accurately define the diabetes susceptibility gene(s) located within the HLA region. To determine whether HLA haplotypes differ between ethnic groups, we compared 105 HLA haplotypes from 55 Mexican-American IDDM patients with 272 haplotypes from 136 IDDM patients of non-Hispanic White descent. The accurate determination of genotypes and haplotypes requires the study of family units. Therefore, all diabetic patients in this study were from studies of families having one or more siblings with IDDM. In the Mexican-American group, HLA-DR3 and -DR4 were the most common HLA-DR alleles and were present in comparable frequencies in the non-Hispanic White group (HLA-DR3, 27% of Mexican-American and 29% of non-Hispanic White haplotypes; DR4, 46% of Mexican-American and 43% of non-Hispanic White haplotypes). However, the HLA-B/DR-containing haplotypes and haplotype frequencies differed between the two groups. Several common haplotypes (B8/DR3, B15/DR4) in the non-Hispanic White group occurred less frequently in the Mexican-American group. In contrast, uncommon haplotypes in the non-Hispanic White group comprised nearly 50% of the DR4-containing haplotypes (B35/DR4, B40/DR4, B44/DR4) in the Mexican-American group. Although both DR3- and DR4-haplotype frequencies differed significantly between the two groups, the relative frequency of DR3- but not DR4-containing haplotypes was similar in both ethnic groups. This adds to the evidence suggesting that different susceptibilities are provided by the haplotypes carrying the DR3 and DR4 alleles.

Iron-deficiency anemia: a medically treatable chronic anemia as a model for transfusion overuse.

PURPOSE: Transfusion practice in patients with iron deficiency was reviewed. PATIENTS AND METHODS: During the study period, records of 265 consecutive patients with an unsaturated iron-binding capacity of greater than 53.7 mumol/L were evaluated for possible iron-deficiency anemia. RESULTS: Two hundred sixty-three patients met the study criteria for iron deficiency. Of these patients, 50 received 1 or more units of red blood cells (RBCs). The transfusion therapy of 12 patients could not be justified; physicians used laboratory results rather than the clinical status of the patients to initiate transfusion therapy. As a result, units of RBCs were transfused to raise the hematocrit to an arbitrarily chosen level. Furthermore, iron therapy was not prescribed for 97 of the 263 iron-deficient patients, including 11 of the patients for whom transfusion was justifiable and 2 patients for whom transfusion could not be justified. Based on records reviewed, no work-up was initiated to identify the cause of iron deficiency in 13 patients, including 4 patients who received transfusions. CONCLUSION: These findings suggest that the evaluation and treatment of iron deficiency, including transfusion therapy for that condition, may be problematic. In view of the risks of blood transfusion therapy, improvement in transfusion practices for iron deficiency should be emphasized.

Neonatal exchange transfusions complicated by transfusion-induced malaria.

Two neonates who became infected with Plasmodium vivax subsequent to exchange transfusion are described. This complication of neonatal exchange transfusion is unusual in that only two other similar cases have been reported to the Centers for Disease Control. Although malaria is an unusual complication, it should be kept in mind when considering the differential diagnoses of fever following neonatal exchange transfusion. The risk of transfusion-induced malaria may be increasing due to the influx of immigrants from areas endemic for malaria. Careful blood donor selection and blood donor education may minimize this risk.

Is it safe to omit the 37 degrees C reading from pretransfusion red blood cell antibody detection testing?

The routine pretransfusion red blood cell antibody detection test (PADT), performed at the authors' institution, consists of a three-phase, saline-antiglobulin technique (immediate spin, 30-minute incubation at 37 degrees C, IgG indirect antihuman globulin test [IAT]), and each phase is examined for hemolysis and agglutination. To determine if it would be safe to omit reading the 37 degrees C phase of the PADT, a 6-year retrospective review of records (February 1986 to February 1992) was undertaken. Of approximately 280,000 sera tested for unexpected red cell alloantibodies, 1480 (.53%) were reactive at only 37 degrees C. Of 1480 sera, 1313 contained alloantibodies of no or questionable significance (eg, anti-Le(a), anti-Leb, and anti-P1), 71 sera contained antibodies of undetermined specificity, and 10 sera were reactive because of rouleaux. Eighty-six serum samples from 53 different patients contained alloantibodies of potential significance (anti-K, anti-E, etc). These 86 sera represented approximately 2.2% of all reactive sera that contained potentially significant alloantibodies. Although most antibodies (approximately 94%) detected only at 37 degrees C were of no or questionable significance, the other 6% could have increased the risk of missing a potentially significant antibody from approximately 1 in every 4700 sera tested to 1 in every 1875 sera tested, had they not been detected. The authors suggest that the increased risk of an acute or delayed hemolytic transfusion reaction would be too high to justify a procedural change. Based on these data, the authors continue to read the 37 degrees C phase of the PADT for hemolysis and agglutination.

Practical aspects of the self-assessment of the issue and administration of blood: a review of two hospitals' experiences.

The transfusion of blood and blood components is usually carried out by personnel who are not under the direct supervision of the transfusion service medical director. Quality assessment and quality improvement processes were described to show how transfusion service medical directors can participate in the initiation, oversight, and assessment of transfusion practices. Such involvement by a transfusion service director is appropriate and consistent with the concept that the responsibility for proper transfusion does not end with the issuance of blood and components by transfusion service personnel. The results and a discussion of the self-assessment studies at two hospitals were also presented.

Practical issues when confronting the patient who refuses blood transfusion therapy.

Caring for the Jehovah's Witness patient poses unique challenges to the medical community. Understanding the patient's viewpoint regarding the refusal of blood and blood products is an essential component in treating these patients effectively. There are currently numerous alternatives to allogeneic blood products that can be used in a variety of settings. The intent of this article is to present the beliefs of Jehovah's Witnesses regarding blood transfusion and to review the use of crystalloids, colloids, hemostatic drugs, erythropoietin, hemodilution, blood salvaging, intraoperative blood-conserving strategies, and artificial blood solutions as alternative treatments for these patients.

The impact of screening a heterogeneous donor population for alanine aminotransferase and hepatitis B core antibody. Experience at a large southern California hospital.

To reduce the transmission of non-A, non-B (NANB) hepatitis, the American Association of Blood Banks (AABB) has recommended that donors be screened for elevated levels of alanine aminotransferase (ALT) and for the presence of antibody to hepatitis B core antigen (anti-HBc). In this survey of 5,336 donors, the authors report the impact of using both of these surrogate tests on a heterogeneous donor population that was composed of white, black, Hispanic, and Asian donors. Hispanic and male donors had relatively high ALT levels, and black and Asian donors had a higher prevalence of anti-HBc than their respective counterparts. The overall impact of using both surrogate tests resulted in a discard rate of 12.1% with a disproportionately high percentage of Hispanic and male donors excluded because of ALT testing and black and Asian donors because of anti-HBc testing. It appears that surrogate testing has a much greater impact on blood collection facilities that rely considerably on Hispanic, Asian, black, or male donors than those that largely draw white or female donors.

Use of a table-top analyzer for predonation screening for alanine aminotransferase--a cost-effective approach?

To reduce the transmission of non-A-non-B hepatitis, the American Association of Blood Banks has required that all blood donations with alanine aminotransferase (ALT) levels above a certain cut-off level to be discarded. This discard rate resulting from high ALT levels was 5.3% at the authors' donor center, which was more than double the expected rate of 2.3%. If blood donors could be tested for their ALT levels before blood donation, unnecessary discarding of blood and related expenses could be eliminated. Therefore, the authors evaluated a table-top ALT analyzer for screening donors before blood donation. The method was precise and linear and correlated well with the SMAC-II analyzer. Based on a cost-savings analysis, the authors found it to be financially beneficial to perform predonation ALT testing. Because the cost of labor and reagents may vary from institution to institution, however, other facilities should perform their own cost-savings analyses before implementing predonation ALT testing.

The risk of bacterial growth in units of blood that have warmed to more than 10 degrees C.

Most transfusion services discard unopened units of blood that have been returned to the blood bank more than 30 minutes after the issuance or have attained a temperature of more than 10 degrees C. The objective of this study was to learn the prevalence of bacterial growth, if any, in the units of blood that were exposed twice, for six hours each time, to room temperature during their refrigerated storage. All of the 396 units cultured were negative except one red cell unit that grew a Bacillus species, probably B. subtilis. Further studies suggested that the growth of B. subtilis was due to laboratory contamination. The authors concluded that more work is needed to study the bacterial growth and the effect on red cell enzymes in the units of blood that are exposed to room temperature for varying periods or are returned to the blood bank after 30 minutes of issuance. If no adverse effect is noted, the policy of not reissuing such units may need revision so that more units could be salvaged.

Can storage of thawed cryoprecipitate be extended to more than six hours?

Fresh-frozen plasma (FFP) and cryoprecipitate both contain Factors I and VIII, however thawed FFP may be stored at 1-6 degrees C for 24 hours, but thawed cryoprecipitate may only be stored at 1-6 degrees C for six hours when used for Factor VIII content. To determine whether it would be safe and effective to extend the storage period of thawed cryoprecipitate from 6 to 24 hours, Factor VIII (and fibrinogen) levels were measured in 25 units of cryoprecipitates immediately on thawing and at 6 hours and 24 hours thereafter. The Factor VIII activity level decreased to 86% of the original activity level within 6 hours, but the drop between 6 and 24 hours was relatively small. Eighty percent of the original activity was still present at 24 hours after thawing. The fibrinogen level decreased to 87% of the original level within 6 hours but remained stable between 6 and 24 hours. Additional testing showed that fibrinogen levels remained stable between 6 and 74 hours. These data suggested that the storage of thawed cryoprecipitate might be extended to 24 hours when this blood product is used for Factor VIII content and to 74 hours when it is used for fibrinogen content. Furthermore, the lack of prohibition on the use of cryoprecipitate that has been thawed for more than six hours and stored at 4 degrees C for its fibrinogen content seems reasonable.

Experience with the routine use of an abbreviated crossmatch.

Three years' experience with the routine use of an abbreviated crossmatch procedure is reported. If a patient had no known history of and/or no currently demonstrable unexpected antibodies, ABO and Rh type specific blood was crossmatched at the time of need by using an immediate spin saline abbreviated crossmatch. Once blood was issued, both a 37 degrees C incubation and an antiglobulin crossmatch were done using the same tube employed for the abbreviated crossmatch. This served as a check that clinically significant antibodies were not overlooked. None of the 19,818 patients transfused following an abbreviated crossmatch suffered an acute hemolytic transfusion reaction as a result of this strategy; however, two patients may have manifested asymptomatic hemolysis. This approach to compatibility testing might be appealing to hospitals faced with fiscal limitations and new regulations affecting hospital reimbursement.

Histocompatibility antigens in sympathetic ophthalmia.

Twenty patients with histopathologically confirmed sympathetic ophthalmia (Group 1) and eight patients with "presumed sympathetic ophthalmia," based on a clinical history of bilateral uveitis occurring within four months of a perforating ocular injury (Group 2), were typed for HLA-A, HLA-B, and HLA-C antigenic determinants by a micro-lymphocytotoxicity technique. HLA antigenic determinants found in Groups 1 and 2 were compared to a control group of 107 patients with sequelae of perforating ocular injuries from accidents, intraocular surgery, or corneal ulcers (Group 3). HLA-A11 antigen showed an increased frequency of 30% in Group 1 (relative risk = 11.0; P less than .002) and an increased frequency of 32% in Groups 1 + 2 (relative risk = 10.5; P less than .0005) compared to Group 3 (frequency = 4%). This finding was validated against a second control group of 453 healthy subjects without ocular disease or trauma (Group 4). This association suggests that a genetic factor may play an important role in the pathogenesis of sympathetic ophthalmia.

Safety in transfusion practices. Red cell compatibility testing issues.

Pretransfusion compatibility testing, if performed properly, helps to maximize the effectiveness of transfusion therapy and to minimize the risk of hemolytic transfusion reactions. Each laboratory should select the procedures and protocols that are best suited to meet their patient care and institutional needs. Quality assessment monitoring of the elements of compatibility testing helps to ensure a high level of safety for patients receiving transfusion therapy.

Parasitic infections and their impact on blood donor selection and testing.

There is currently less than a one in a million chance that a blood transfusion within the United States will be complicated by a parasitic infection. However, changes in population demographics and increases in international travel and immigration may all contribute to an increase in the number of parasitemic individuals who present as prospective blood donors. Consequently, a need may arise to develop new policies to prevent transfusion-transmitted parasitic infections. In the present review, the following parasitic infections of concern to the safety of the US blood supply will be discussed: malaria, Chagas' disease, babesiosis, leishmaniasis, toxoplasmosis, and microfilariasis.

The risk of an overt hemolytic transfusion reaction following the use of an immediate spin crossmatch.

The major crossmatch must include an anti-human globulin test, unless the transfusion recipient has no apparent significant unexpected antibodies, in which case the use of only an immediate spin crossmatch method is considered acceptable. However, a minority of laboratories utilize only an immediate spin crossmatch as their routine major crossmatch, possibly because contemporary antibody screening tests occasionally miss detecting some unexpected antibodies, and these missed antibodies are more often detected by the anti-human globulin crossmatch than by the immediate spin crossmatch. In the present study, 20 hospitals were surveyed to determine how often an acute hemolytic transfusion reaction would occur when only an immediate spin crossmatch was used as the major crossmatch method. During the study period, 1.3 million immediate spin crossmatches were performed, and five patients experienced acute overt hemolytic transfusion reactions that were believed to be caused by antibodies that were missed by both the antibody screening test and immediate spin crossmatch (one hemolytic event per 250,000 immediate spin crossmatches). The implicated antibodies were anti-Jka, anti-Wra, anti-C, anti-c, and anti-Kpa. These survey data demonstrate that the routine crossmatching of blood using an immediate spin crossmatch may rarely result in an acute hemolytic transfusion reaction if the antibody screening cells used during pretransfusion compatibility testing fail to detect some clinically significant red blood cell antibodies.

Safety in transfusion practice. Is it safe to eliminate the major crossmatch for selected patients?

If a patient has no clinically significant unexpected antibodies, a major crossmatch is not required prior to blood transfusion so long as a test method that demonstrates ABO incompatibility is done. In this study, the safety of using a noncrossmatch method for detecting ABO incompatibility was compared with the use of an immediate spin crossmatch (ISCX). This noncrossmatch method consisted of the duplicate ABO testing of blood recipients, the repeated ABO testing of donor blood, and a clerical check to assure that only ABO matched or compatible blood was selected for transfusion. During the one-year study, 7124 patient samples were tested in duplicate for ABO, 26,942 U of red blood cells received from blood collection facilities were retested for ABO, and 23,962 U of blood selected for transfusion based on the noncrossmatch method were tested by an ISCX. ABO test results were concordant for 7115 of 7124 patient samples and discordant for nine. Seven of the nine discordant patient test results were resolved prior to transfusion, and two were inadvertently overlooked. ABO test results were concordant for 26,922 of 26,942 donor units and discordant for 20. Seventeen of the 20 discordant donor test results were resolved prior to transfusion and three were inadvertently overlooked. Two ABO incompatibilities were missed by the noncrossmatch method but were detected by the ISCX. Unless clerical errors can be totally eliminated, it may be safer to retain the ISCX.

Blood transfusion in medically treatable chronic anemia. Pernicious anemia as a model for transfusion overuse.

Transfusion practice in patients with treatable, readily recognizable, chronic anemia was reviewed because such patients only infrequently need to be transfused. Pernicious anemia with hemoglobin concentration below 100 g/L was chosen as the model for this assessment. Sixty-two (51%) of 122 patients received blood transfusion, although most patients had chronic, low-grade symptoms despite their low hemoglobin levels and could have been satisfactorily managed without transfusion. Only 34 of the 122 had findings suggesting an urgent need to raise the blood cell count, but their transfusion rate (44%) was no different from that in patients without such findings. These observations in pernicious anemia indicate that transfusion of patients with medically reversible anemia is a common problem. They further suggest that current transfusion usage overemphasizes laboratory results (ie, hemoglobin levels) at the expense of clinical assessment of severity of symptoms. Improvement of current practice is needed, particularly in view of valid concerns about the serious side effects of transfusion, shortages of available blood resources, and health care costs.