Prevention of transfusion-associated cytomegalovirus infection. Practice parameter. American Society of Clinical Pathologists.

This practice guideline represents the opinions and recommendations of the author(s), the American Society of Clinical Pathologists (ASCP) Practice Parameters Committee and the ASCP Board of Directors regarding the appropriate strategies for each clinical condition or laboratory test discussed in this guideline. This guideline is designed primarily as an educational resource for physicians in the provision of quality medical services. Adherence to this guideline is completely voluntary and does not necessarily assure a successful medical treatment or result. This practice guideline should not be considered inclusive of all proper procedures and tests or exclusive of other procedures or tests that are reasonably directed to obtaining the same results. The physician should apply his or her own professional judgment to the unique clinical circumstances presented by the particular procedure or test. Physicians are encouraged to document the reasons for whatever procedure or test they use (whether or not in conformance with this guideline). Physicians should also take care to consider other medical and scientific advances that are available after the date of adoption of this guideline. This practice guideline was developed exclusively for the purposes set forth above and not for use in connection with matters involving reimbursement, credentialing, or utilization review.

Use of irradiated blood components: practice parameter.

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare but fatal potential complication of transfusions. It is mediated by immunocompetent donor lymphocytes that cannot be eliminated by the recipient. Patients at risk for developing TA-GVHD are those who have a profound deficiency in cell-mediated immunity or those who share histocompatibility antigens with the donor and do not recognize the donor cells as foreign. Irradiation of cellular blood components is currently the only acceptable method for prevention of TA-GVHD. This practice guideline identifies the patient population who should receive irradiated blood components and describes the technical aspects of blood component irradiation that may affect the safety of the final product.

Prenatal diagnosis of the RhD fetal blood type on amniotic fluid by polymerase chain reaction.

OBJECTIVE: To assess the accuracy of a molecular assay for the determination of the fetal RhD status on amniotic fluid (AF)samples. METHODS: Amplification of DNA by polymerase chain reaction of a common sequence of the RhD and CE genes and of a unique sequence of the RhD gene was performed on AF directly or after DNA extraction. Samples of AF obtained from patients undergoing amniocentesis for standard obstetric indications were used for the study. RESULTS: Amplification of DNA was successful on 112 of 114 samples. One hundred four fetuses were found to be RhD positive and eight were found to be RhD negative. Serologic confirmation of the RhD blood type was available on 108 samples and DNA diagnosis was correct in all cases. CONCLUSION: Polymerase chain reaction can be used to determine accurately the fetal RhD blood type from AF samples.

Alterations in plasma volume and protein during cycle exercise throughout pregnancy.

The purpose of this investigation was to determine the effects of cycle exercise on maternal plasma volume (PV) and protein dynamics during pregnancy. Sixteen healthy gravidas (age = 23 +/- 4.6 yr) cycled for 5 min (75 W) at 4 wk intervals throughout term. Venous blood samples were drawn immediately prior to and during the last minute of exercise. Relative (percent) PV changes during exercise were calculated from hematocrit ratios and hemoglobin concentrations. Plasma was analyzed for total protein ([TP]) and albumin ([ALB]) concentrations and colloid osmotic pressure (COP). Resting blood volumes were also estimated (carbon monoxide rebreathing) so that absolute PV (ml) and TP and ALB contents (g) could be determined. COP increases (P less than 0.001) during exercise were similar at all gestational ages. Plasma volume, TP, and ALB decreased during exercise with significantly (P less than 0.001) greater losses occurring from 29-32 wk gestation. This may indicate an increase in capillary permeability to large molecules when vascular volume was highest.

Case reports: delayed hemolytic transfusion reaction in sickle cell disease.

This article reports the details of delayed hemolytic transfusion reactions in four patients with sickle cell disease. These cases demonstrate the characteristics of the reactions, the significant risks involved, and the principles useful in diagnosis and treatment. Patients with sickle cell disease are at particular risk for delayed hemolytic transfusion reactions because they may be transfused at intervals over many years; they frequently form alloantibodies because of antigenic differences from the donor population; and they may receive emergency care in different hospitals where transfusion records are not available. In addition, exchange transfusions, which are often used for patients with sickle cell disease and which were given in three of these cases, raise the risks through increased exposure to foreign erythrocyte antigens and through an increased volume of erythrocytes susceptible to hemolysis. It was concluded that the hazards of these transfusion reactions justify preventive measures, such as extended erythrocyte phenotyping of patients with sickle cell disease and extended phenotypic matching of transfused cells.

Du phenotyping by the rosette technique when the direct antiglobulin test is positive.

The rosette technique provides a simple rapid and accurate procedure for Du phenotyping of red blood cells (RBCs) with a positive direct antiglobulin test (DAT) due to antibodies other than those of the Rh system. We used Sebring and Polesky's rosette technique to test RBCs with positive DATs. Characteristic microscopic agglutination was observed for the Du phenotype which was different from the mixed-field agglutination seen as positive rosettes in feto-maternal hemorrhage (FMH). The microscopic "starry-sky" pattern typical for FMH-positive rosettes is easily differentiated from the uniform agglutination produced by the D phenotype. The rosette technique was performed on 202 Rh negative cord RBCs out of 4815 cord cells with a positive DAT. Parallel testing for Du by the chloroquine elution and antihuman globulin (AHG) test was done on 67 of the 202 cases. Four Du RBCs that were identified by the rosette technique were confirmed by the chloroquine Du technique The rosette technique proved to be time saving and as sensitive as the routinely performed elution technique for removal of antibodies followed by the AHG Du test.

Resolution by erythrocytapheresis of the exposure of an Rh-negative person to Rh-positive cells: an alternative treatment.

Acute trauma with severe bleeding caused the unavoidable transfusion of Rh-positive red cells (RBCs) to a young, childless, Rh-negative woman during surgery. Of the 10 units of RBCs given, 6 were Rh positive. An alternative treatment for large-volume exposure involves the removal of some of the Rh-positive cells transfused at a time when the patient's condition could not be jeopardized by the shortage of Rh-negative RBCs. It is believed that the combination of erythrocytapheresis followed by Rh immune globulin treatment was successful, when immunoprophylaxis alone might not have been. It is strongly recommended that partial RBC exchange for the removal of the unwanted RBCs be considered in addition to Rh immune globulin treatment in cases of large-volume exposure such as the one presented.

Detecting bacteria in platelet concentrates by use of reagent strips.

BACKGROUND: Iatrogenic infection of immunosuppressed or immunocompromised hosts secondary to receipt of blood components containing bacteria may result in serious adverse outcomes. Measurement of pH and glucose by use of inexpensive reagent strips has been proposed as a practical means of screening for bacteria in platelet concentrate (PC) units. STUDY DESIGN AND METHODS: Glucose and pH were measured in 3093 PC units by use of reagent strips (Multistix, Bayer Corp.) to screen for bacterial content. Any PC classified by the reagent strip method as containing bacteria was subsequently cultured to confirm the presence and quantity of bacteria present. RESULTS: Thirty of 3093 PC units were classified as containing bacteria by the reagent strip method. Two of the 30 PC units positive by the reagent strip method were also positive by standard bacterial culture technique. Bacillus cereus was isolated from both units. CONCLUSION: Screening PC units by the reagent strip method resulted in 9.7 units per 1000 being wasted, but prevented two patients from receiving a PC unit containing B. cereus.

Physiologic observations of pregnant women undergoing prophylactic erythrocytapheresis for sickle cell disease.

Five women in the second or early third trimester of pregnancy underwent prophylactic partial red cell exchange by automated erythrocytapheresis for sickle cell disease. The purpose of this pilot study was to characterize the hematologic, hemodynamic, and metabolic changes associated with this procedure. Pretransfusion hematocrit increased 49 percent by 3 to 5 days after the transfusion. Paired observations indicate a 14-percent drop in maternal oxygen consumption. There was a slight tendency for reduced posttransfusion cardiac output that resulted primarily from changes in maternal heart rate and not from changes in stroke volume. Left ventricular contractility also tended to decrease after transfusion. Neither fetal bradycardia nor alteration in the umbilical circulation by Doppler ultrasound was observed during the transfusion procedures. Despite substantial hematologic alterations, this procedure is associated with small or negligible changes in maternal hemodynamic and metabolic function for minimally symptomatic pregnant patients with sickle cell disease.

Incidence of cytomegaloviremia in blood-bank donors and in infants with congenital cytomegalic inclusion disease.

During a 15-month period, cytomegalovirus (CMV) isolations were attempted from leukocytes derived from 290 healthy blood-bank donors. The major proportion of the specimens were tested 2 to 5 hr after donation. However, CMV was not recovered from any of the specimens examined. At the time of donation, 75% of donors had CMV complement-fixing antibodies demonstrable in titers of 10 to >/=320. The age of the study group ranged from 17 to 57 years. During the same time period and with the use of identical isolation techniques, postnatal cytomegaloviremia was demonstrated in four infants with cytomegalic inclusion disease. Failure to detect cytomegaloviremia in 290 normal blood donors questions its occurrence outside pathological conditions. These results do not support the concept that CMV infection, concurrent with post-transfusion mononucleosis syndrome, is transmitted through the blood donor's leukocytes.

Serum alanine aminotransferase of donors in relation to the risk of non-A,non-B hepatitis in recipients: the transfusion-transmitted viruses study.

To evaluate the incidence of post-transfusion hepatitis and factors influencing its occurrence, the Transfusion-Transmitted Viruses Study prospectively followed 1513 transfusion recipients from 1974 through 1979. The attack rate for non-A,non-B hepatitis was 10 per cent. The incidence of hepatitis was directly related to the alanine aminotransferase (ALT) level in blood donors. In recipients of multiple transfusions of blood that had no donor-ALT level above 29 IU per liter the attack rate was 6 per cent or less; at higher donor-ALT levels the attack rate increased progressively, reaching 45 per cent in recipients of units with an ALT of 60 IU or greater. A similar relation was observed among recipients of single units of blood. Moreover, hepatitis developed in 10 of 11 recipients of two units with an ALT level of 45 IU or greater. These data indicate that screening blood for ALT levels would reduce the incidence of non-A,non-B post-transfusion hepatitis.

Hepatitis B virus antibody in blood donors and the occurrence of non-A, non-B hepatitis in transfusion recipients. An analysis of the Transfusion-Transmitted Viruses Study.

Patients who received transfusions and nontransfused control patients were followed to assess the incidence and cause of post-transfusion hepatitis and to identify donor factors that might relate to risk of hepatitis. We evaluated as risk factors in donors the presence of antibody to hepatitis B virus compared with elevated alanine aminotransferase (ALT) level. Units of blood that were positive for antibody to hepatitis B core antigen (anti-HBc) were associated with a twofold to threefold greater risk of non-A, non-B hepatitis in the recipients than were units without anti-HBc. In the absence of specific serologic tests for non-A, non-B agents, screening of donors for anti-HBc might be considered. Our data suggest that the incidence of non-A, non-B hepatitis might have been reduced by about one third by such screening. However, elevated ALT levels in donors had a similar association with non-A, non-B hepatitis in recipients but would have resulted in fewer units of blood being discarded than would screening for anti-HBc.

Non-A, non-B hepatitis transmission in chimpanzees: a project of the transfusion-transmitted viruses study group.

Experimental transmission of non-A, non-B hepatitis was apparently accomplished in 5 chimpanzees following inoculation with presumably infectious human sera. Administration of sera from implicated donors with normal alanine aminotransferase (ALT) values, as well as from those with abnormal ALT levels, resulted in the development of ALT abnormalities in the inoculated chimpanzees. Transmission from donors with normal ALT values implies that healthy carriers of non-A, non-B virus exist. Evidence is presented which indicates that a period of viremia precedes the clinical illness by at least 12 days.