Granulocyte transfusions in hematologic malignancy patients with invasive pulmonary aspergillosis: outcomes and complications.

BACKGROUND: Granulocyte transfusions (GTXs) have been used successfully as an adjunctive treatment option for invasive infections in some neutropenic patients with underlying hematologic malignancy (HM). PATIENTS AND METHODS: We sought to determine the impact of GTX as an adjunct to antifungal therapy in 128 patients with HM and prolonged neutropenia (≥14 days) with a proven or probable invasive aspergillosis (IA) infection by retrospectively reviewing our institutional database. RESULTS: Fifty-three patients received GTX and 75 did not. By univariate analysis, patients with invasive pulmonary aspergillosis who received GTX were less likely to respond to antifungal therapy (P = 0.03), and more likely to die of IA (P = 0.009) when compared with the non-GTX group. Among patients who received GTX, 53% developed a pulmonary reaction. Furthermore, IA-related death was associated with the number of GTX given (P = 0.018) and the early initiation of GTX within 7 days after starting antifungal therapy (P = 0.001). By multivariate competing risk analysis, patients who received GTX were more likely to die of IA than patients who did not receive GTX (P = 0.011). CONCLUSIONS: Our study suggests that GTX does not improve response to antifungal therapy and is associated with worse outcomes of IA infection in HM patients, particularly those with pulmonary involvement.

Immediate adverse reactions to platelet transfusions: whole blood derived versus apheresis platelets.

The transfusion of whole blood derived platelets (WBDPs) or apheresis platelets (APs) is standard support for cancer patients. However, disputes remain about which type of platelets are ideal in terms of efficacy, cost, and the risk of adverse reactions. This cross sectional study included 141 cancer patients who underwent chemotherapy or hematopoietic progenitor cell transplantation and received platelet transfusions at The University of Texas M.D. Anderson Cancer Center between 2002 and 2003 were retrospectively evaluated. A total of 141 patients who did not differ significantly in terms of age or sex had a reaction to transfusions (WBDPs, n=123; APs, n=18), for a frequency of 0.66% in patients who received WBDPs and 0.45% in patients who received APs, but this difference was not statistically significant (p=0.13). More WBDP-related reactions occurred in patients transfused with older platelets (>2 days old) than in patients transfused with fresh platelets, but the difference compared with AP-associated reactions was not statistically significant. However, the rate of reactions to WBDP may increase if WBDPs are stored for a prolonged time (>2 days). Until evidence becomes available that clearly refutes this; the more fresh platelets as possible may be used.

A prospective, randomized, double-blind study, comparing unirradiated to irradiated white blood cell transfusions in acute leukemia patients.

A prospective, randomized double-blind study comparing the effects of irradiated and unirradiated white blood cells was conducted in 108 acute leukemia patients with life-threatening infections, refractory to antibiotics. The study demonstrated no significant improvement in 30-day survival or overall survival. Transfusion of unirradiated white cells did not compromise the patient's opportunity to undergo allogeneic stem cell transplant, nor the success rate or overall survival after allogeneic transplant. The important positive finding in this study was that the unirradiated white cells produced a significantly higher increment in circulating granulocytes and in a higher proportion of patients granulocyte count exceeded 1000 per microliter, approaching normal concentrations. The increase in the number and the improved survival of the unirradiated granulocytes suggest that this procedure might potentially be a method to improve the utility of granulocyte transfusions and merits further investigation. The study demonstrated non-inferiority for unirradiated white cells. There were no harmful effects such as graft-versus-host disease, indicating that such studies would be safe to conduct in the future.

The role and impact of the transfusion medicine consultation service in the management of patients in the hematopoietic transplant service: A retrospective analysis.

BACKGROUND: Adverse reactions secondary to transfusion of incorrect blood components can be fatal. We have established numerous processes to prevent these reactions in patients with cancer who continuously need blood component support, especially hematopoietic transplant recipients. The development of an active transfusion medicine consultation service at our institution to serve patients undergoing hematopoietic transplantation has led to more organized and simpler management of providing blood components to such patients. STUDY DESIGN AND METHODS: Safety tools were employed to attain our goal of providing safe blood components to hematopoietic transplant recipients. These tools were consultation request forms, blood component selection stickers on the patients' charts, and transfusion medicine physician consultation notes posted in the patients' medical records. One hundred randomly selected hematopoietic transplant recipients were reviewed over 16 months. Fifty patients received blood components from ABO-compatible donors, whereas the other 50 patients received components from ABO-incompatible donors. Deviation reports regarding the issuance of blood components in these patients over the study period were reviewed retrospectively. RESULTS: We identified eight reported deviations from the recommended blood components: red blood cells in one case, fresh frozen plasma in one case, single donor platelets in one case, and random donor platelets in five cases. Our transfusion service issued all eight components, but none of them were transfused. In all eight cases, the blood components were intended for transfusion to ABO-mismatched hematopoietic transplant recipients. Nurses identified the incorrect blood components by verifying the recommended blood groups on the patients' chart stickers, returned the components to the transfusion service, and transfused the correct blood components. CONCLUSION: Use of these safety tools has improved the safety culture regarding transfusion of blood components in hematopoietic transplant recipients at our institution.

Efficacy of prophylactic transfusions using single donor apheresis platelets versus pooled platelet concentrates in AML/MDS patients receiving allogeneic hematopoietic stem cell transplantation.

Superiority of single-donor apheresis platelets (SDAP) over pooled platelet concentrates (PPC) transfusions is largely assumed, but unproven. We hypothesized that prophylactic SDAP and PPC transfusions are clinically equivalent after allogeneic hematopoietic stem cell transplants (HSCT). We studied all transfusions administered to 33 patients with AML/MDS during the first 100 days after busulfan-based, myeloablative HSCT. All donor-recipient pairs were ABO identical. Transfusion threshold was a platelet count < or =15 x 10(9)/l. The corrected increment (CCI) was used for all comparisons. Median time to platelet engraftment was 13 days (n=30). PPC transfusions (n=105) were ABO compatible, while 10% of 41 SDAP were not (P=0.006). Median post-transfusion platelet count was 51K/microl (5-118K) after SDAP and 36K/microl (3-115K) after PPC (P=0.0004). Median CCI was 14.178 (SDAP) versus 7.793 (PPC) (P=0.0001). Median time to another transfusion was 3 days (SDAP) and 2 days (PPC; P=0.3). In the week following any given transfusion, the median number of new transfusions was similar (n=2), as well as the need of further transfusion (16 versus 24%, P=0.2). A total of 17% of SDAP and 30% of PPC transfusions were labeled 'ineffective' (P=0.1). There were two non-lethal hemorrhage episodes (6%). SDAP transfusions produced better platelet counts, but SDAP and PPC were equally effective in preventing hemorrhage.

Transfusion of leukoreduced cellular blood components from cytomegalovirus-unscreened donors in allogeneic hematopoietic transplant recipients: analysis of 72 recipients.

Leukoreduction of blood components has been considered a safe alternative to screening donors for CMV. The objective of this study is to analyze the effectiveness of bedside leukoreduction in preventing CMV transmission. We retrospectively studied 72 transplant recipients and donors who were CMV-seronegative pairs. All patients were transfused with CMV-unscreened cellular blood products leukoreduced at the bedside using leukoreduction filters. Quality control measures performed monthly in our leukoreduced blood components consistently demonstrated that at least 95% of the units sampled meet the leukoreduction criterion established by the American Association of Blood Banks standards. The CMV status of the recipients and donors was determined before transplantation by the latex agglutination assay. Recipients were observed for at least 100 days after transplantation. CMV cultures of urine, buffy coat, bone marrow, and bronchial washings were done weekly when indicated. CMV antigenemia testing was performed twice weekly: 11 transplant recipients seroconverted after transplantation. One patient was positive for CMV antigenemia 4 months after transplantation, but did not have CMV infection. Two of 61 patients who were not seroconverted were CMV antigenemia positive and did not have CMV infection: leukoreduction of cellular blood products is an efficient method of preventing CMV infection.

Bedside leukoreduction of cellular blood components in preventing cytomegalovirus transmission in allogeneic bone marrow transplant recipients: a retrospective study.

BACKGROUND AND OBJECTIVES: Cytomegalovirus (CMV) infection continues to be a major complication of bone marrow transplants (BMTs). Administration of leukoreduced unscreened cellular blood products at the bedside has been shown to be effective in preventing CMV transmission via transfusions in CMV-seronegative bone marrow transplant recipients who receive their transplants from CMV-seronegative donors. The aim of this study was to determine whether CMV infection occurred in CMV-seronegative BMT patients who received CMV-seronegative donor marrows and CMV untested blood products leukodepleted at the bedside. DESIGN AND METHODS: We collected data over a 2-year period from patients undergoing allogeneic transplantation who received leukoreduced cellular blood components that were not screened for CMV. All CMV-seropositive patients and donors were excluded from the study. The CMV status of both the donors and the patients was determined before the transplantations. CMV cultures of urine, blood buffy coat, bone marrow samples and bronchial washings were performed if necessary in patients. RESULTS: Thirty-six CMV-seronegative patient-donor pairs were included in the study. Five patients (13.89%) were serologically reactive, but their CMV cultures were negative and they did not show signs or symptoms of CMV infection. These patients received intravenous immunoglobulin and thus could have acquired anti-CMV passively. INTERPRETATION AND CONCLUSIONS: The confidence interval in this study is 0/36 incidence of CMV infection. Our present findings support those of prior studies showing the effectiveness of filtered unscreened blood components as an alternative transfusion support for CMV-seronegative marrow transplant recipients. Studies in larger number of patients are warranted.

Controlled trial of filgrastim for acceleration of neutrophil recovery after allogeneic blood stem cell transplantation from human leukocyte antigen-matched related donors.

The rapid recovery of hematopoiesis after allogeneic blood stem cell transplantation has been attributed to the quality and quantity of hematopoietic progenitors in the blood stem cell grafts from filgrastim-stimulated donors. To determine whether further stimulation with filgrastim after transplantation would affect hematopoietic recovery, a prospective, randomized, controlled study was performed. Forty-two adult recipients of allogeneic blood stem cells from human leukocyte antigen-matched related donors were randomized to receive 10 microg/kg per day filgrastim subcutaneously from day 1 through neutrophil recovery or no growth factor support after transplantation. There was no significant difference between the 2 groups in the number of CD34(+) cells infused (median, 4.8 vs 4.3 x 10(6)/kg). Graft-versus-host (GVHD) disease prophylaxis consisted of tacrolimus and steroids for 9 patients and tacrolimus and minimethotrexate for 33 patients. The group receiving filgrastim had a shorter time to neutrophil levels greater than 0.5 x 10(9)/L (day 12 vs day 15, P =.002) and to neutrophil levels greater than 1.0 x 10(9)/L (day 12 vs day 16, P =.01). The filgrastim group also had a trend for earlier discharge (day 16 vs 20, P =.05). There was no significant difference between the groups in time to platelet recovery, number of transfusions, regimen-related toxicity, infection, incidence of GVHD, relapse, survival, or hospital charges. It can be concluded that the administration of filgrastim after allogeneic blood stem cell transplantation shortens the time to neutrophil recovery. (Blood. 2001;97:3405-3410)

Enhanced circulatory parameters of human platelets cryopreserved with second-messenger effectors: an in vivo study of 16 volunteer platelet donors.

Platelet transfusion represents an important component of the therapy for thrombocytopenic patients. Prolonged storage capabilities for platelets would alleviate many problems associated with blood banking. Unfortunately, current cryopreservation methods are complex to implement and result in loss of cell number and functional activity. Previous in vitro studies have shown that the use of ThromboSolTM, a platelet-stabilizing formulation, in the cryopreservation of platelets results in significant retention of cell number and in vitro functional activities in addition to reducing the DMSO requirement to only 2%. We evaluated the in vivo circulatory parameters of platelets cryopreserved with ThromboSol. Single donor platelet units were obtained from healthy volunteers (n = 16); the units were then split and cryopreserved with either ThromboSol and 2% DMSO or 6% DMSO alone. Following storage at -80 degrees C for 7-10 d the samples were thawed, washed and radiolabelled with either 51Cr or 111In. The paired samples were then mixed and reinfused into the autologous volunteer. At various time intervals following transfusion a blood sample was drawn and the quantity of circulating labelled platelets was determined. The percent recovery and survival time was determined by multiple-hit analysis. The ThromboSol-treated platelets, as compared to the 6% DMSO-treated platelets, displayed statistically higher percent recovery (40.2% v 28.8%) and survival time (166.3 h v 152.1 h). These results demonstrated that platelets cryopreserved with ThromboSol displayed superior in vitro and in vivo characteristics as compared to the standard 6% DMSO method. The use of ThromboSol allowed for a 3-fold reduction in the DMSO concentration in conjunction with a 40% increase in circulating cell number and normal survival times.

Transfusion support using filtered unscreened blood products for cytomegalovirus-negative allogeneic marrow transplant recipients.

It has been suggested that leukoreduced unscreened blood products can be used as an alternative to components from cytomegalovirus (CMV)-seronegative donors in order to prevent transmission of CMV from transfusions for CMV-seronegative marrow transplant recipients with CMV-seronegative donors, but confirmatory data are lacking. A retrospective chart review was undertaken for patients undergoing allogeneic transplantation over a 4-year period during which blood products were filtered for CMV-seronegative patients with CMV-seronegative donors when CMV-seronegative components were not available. Forty-five CMV-seronegative patient-donor pairs were identified. Only one patient developed CMV disease (pneumonia) and no other patients developed an infection. In this group of patients, the rate of CMV infection was 2.7% (95% CI, 0-8%) by life-table analysis. We conclude that filtered unscreened blood products as partial transfusion support for CMV-seronegative marrow transplant recipients were associated with a low incidence of CMV infection, justifying further evaluation of filtered blood products as total transfusion support for this patient population. However, since CMV infections still occur, continued surveillance by periodic culture or other techniques is warranted.

Evaluation and comparison of three mobilization methods for the collection of granulocytes.

BACKGROUND: Cancer chemotherapeutic regimens have become more potent and myeloablative. As a consequence, morbidity and mortality due to opportunistic infections have become a major challenge. The provision of adequate doses of viable granulocytes has thus become an important approach for circumventing the problem. A schedule for collecting therapeutic numbers of cells with minimal donor toxicity has yet to be established. STUDY DESIGN AND METHODS: An investigation of three mobilization schedules for the collection of granulocytes for transfusion--granulocyte-colony-stimulating factor (G-CSF) 5 micrograms per kg daily; G-CSF 5 micrograms per kg every other day, and prednisone 60 mg given orally (20 mg doses at 17 hours, 12 hours, and 2 hours before the collection). RESULTS: A total of 464 apheresis procedures involving 163 healthy donors were analyzed. Prednisone caused a small increase in the white cell (WBC) counts over the collection days, while G-CSF every other day and daily schedules improved WBC counts to 145 and 160 percent, respectively (p = 0.004). Similarly, administration of G-CSF daily and every other day mobilized higher yields of granulocytes over the collection days, compared to the prednisone schedule (170% and 180% vs. 105%; p = 0.02). CONCLUSION: Compared with prednisone, higher WBC yields were achieved by G-CSF stimulation; G-CSF given every other day is as effective as daily G-CSF administration for the recruitment of granulocytes, which makes the mobilization procedure more cost-effective.

Costs of blood transfusion: a process-flow analysis.

PURPOSE: To determine the cost of transfusing 2 units (U) of packed RBCs at a comprehensive cancer center. METHODS: We performed a process-flow analysis to identify all costs of transfusing 2 U of allogeneic packed RBCs on an outpatient basis to patients with either (1) solid tumor who did not undergo bone marrow transplantation (BMT), (2) solid tumor who underwent BMT, (3) hematologic malignancy who did not undergo BMT, (4) hematologic malignancy who underwent allogeneic BMT, or (5) hematologic malignancy who underwent autologous BMT. We conducted structured interviews to determine the personnel time used and physical resources necessary at all steps of the transfusion process. RESULTS: The mean cost of a 2-U transfusion of allogeneic packed RBCs was $548, $565, $569, $569, and $566 for patients with non-BMT solid tumor, BMT solid tumor, non-BMT hematologic malignancy, allogeneic BMT hematologic malignancy, and autologous BMT hematologic malignancy, respectively. Sensitivity analysis showed that total transfusion costs were sensitive to variations in the amount of clinician compensation and overhead costs, but were relatively insensitive to reasonable variations in the direct costs of blood tests and the blood itself, or the probability or extent of transfusion reaction. CONCLUSION: The costs of the transfusion of packed RBCs are greater than previously analyzed, particularly in the cancer care setting.

Treatment of neutropenia-related fungal infections with granulocyte colony-stimulating factor-elicited white blood cell transfusions: a pilot study.

Neutropenia-related fungal infections can be life-threatening despite antifungal therapy. We evaluated the role of recombinant granulocyte colony-stimulating factor (rG-CSF)-elicited white blood cell (WBC) transfusions in patients with neutropenia-related fungal infections. Adult patients with hematologic malignancies, absolute neutrophil counts (ANC) <500/microl and fungal infections refractory to amphotericin B, received daily transfusions of rG-CSF-elicited and irradiated WBC transfusions from related donors. Donors received 5 microg/kg/day of rG-CSF subcutaneously. Donors achieved a mean ANC of 29.4 x 10(3) per microliter. The mean yield of neutrophils per transfusion was 41 x 10(9) (range, 10-116). Fifteen patients received a median of eight transfusions (range, 3-16). Fourteen patients had received rG-CSF for a median of 12 days. The median ANC baseline was 20/microl. Eleven patients had favorable responses and eight of them remained free of infection 3 weeks after therapy. Favorable responses occurred among patients with better Zubrod performance status (median, 3 vs 4) and shorter duration of both profound neutropenia (median, 15 vs 25 days) and active infection (median, 8 vs 17 days). The mean 1- and 24-h post-transfusion ANCs were 594/microl (range, 98-1472/microl) and 396/microl (range, 50-1475/microl), respectively. Adverse reactions were observed in nine of 35 donors and in the recipients of six of 130 transfusions. rG-CSF-elicited WBC transfusions may be a safe and promising approach for treating neutropenia-related fungal infections.

Assessing the efficiency of leukoreduction of cellular blood components. Use of a simplified formalin-fixation and batch-counting method.

To simplify the quality control procedure used to determine the efficiency and consistency of bedside leukoreduction, a counting protocol using prefiltration and postfiltration aliquots fixed in 10% formaldehyde was designed. To assess the reliability of the values obtained by counting the formalin-fixed samples, a parallel study was performed using our standard protocol of counting fresh propidium iodide-stained samples in a Nageotte chamber under a fluorescent microscope. A total of 30 single-donor platelet concentrates and 30 units of packed red blood cells were analyzed in parallel using the standard and formalin-fixation methods. Furthermore, the aliquots fixed in formaldehyde were split and counted at 1, 3, and 30 days. The results showed no significant quantitative difference between the two methods. Of note is that the counts in formaldehyde-fixed samples at 1, 3, and 30 days were consistent among themselves. The formaldehyde fixation of samples obtained for quality control of leukoreduction allows blood collection and storage at 4 degrees C and batch counting when and where convenient.

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.

Clinical toxicity and laboratory effects of granulocyte-colony-stimulating factor (filgrastim) mobilization and blood stem cell apheresis from normal donors, and analysis of charges for the procedures.

BACKGROUND: Apheresis of granulocyte-colony-stimulating factor (filgrastim)-mobilized blood stem cells from normal donors is now being used in place of a marrow harvest in transplantation. How the adverse effects of and charges for this procedure compare with those of the standard marrow harvest is not known. STUDY DESIGN AND METHODS: Forty consecutive normal subjects who received filgrastim 96 micrograms/kg) subcutaneously twice daily for 4 to 6 days in preparation for apheresis were monitored prospectively by clinical and laboratory evaluation. RESULTS: Sixty-two percent of the subjects required oral analgesics. None discontinued filgrastim prematurely. Bone pain (82%), headache (70%), fatigue (20%), and nausea (10%) were reported. Filgrastim caused a mean eightfold increase in neutrophil counts, a mean twofold increase in lymphocyte counts, a mean twofold rise in alkaline phosphatase and lactate dehydrogenase levels, and minor changes in serum potassium, magnesium, and uric acid. Adverse events and laboratory effects resolved within 7 days after apheresis. No apheresis stem cell donor required transfusion or hospitalization, and only one required an additional clinic visit after completion of apheresis. By comparison, a retrospective analysis of 33 normal marrow donors demonstrated that all received transfusion(s), 3 were hospitalized, 3 required additional clinic visits after the marrow harvest. The median total charges related to the two procedures were comparable (p = 0.43), although the charges were significantly lower for donors requiring only one apheresis procedure (p = 0.002). CONCLUSION: Filgrastim mobilization and apheresis of blood stem cells constitute a safe, well-tolerated, and comparable or less expensive alternative to the traditional marrow harvest.

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.

Autologous deposit of blood by oncology patients: an evaluation of actual use and wastage.

BACKGROUND: Transfusions of autologous deposited blood have continued to grow since the 1980s. Together with the growth in the deposit of autologous blood, issues such as appropriateness of indications, reimbursement, cost effectiveness, etc., have emerged and require addressing. Also, the patient's concerns about safety of the blood supply must be taken into account. METHODS: We conducted a 20-week study to determine the collection and transfusion/wastage of autologous blood and the need to transfuse additional allogeneic units of packed red blood cells. The disposition of every autologous unit was followed until its disposal. RESULTS: One hundred fifty-seven patients deposited 260 units of autologous blood. Of these, 144 units (55.4%) were transfused whereas 44.6% were discarded. In addition, 25 or 157 patients (15.9%) received an additional 58 units of allogeneic blood. CONCLUSION: These data demonstrate that there are surgical procedures where autologous blood is drawn unnecessarily whereas others could afford a higher number of autologous blood deposits. Physicians may be pressured by patients into ordering autologous blood deposits, to allay fear of patients about safety of the blood supply. It is important that health care professionals undergo periodic education to be able to address patient's apprehension about safety of the blood supply.

Implications of human T-lymphotropic virus type-I and type-II testing in donors and patients.

The retroviruses known as Human T-Lymphotropic Virus Types I and II (HTLV-I and -II) were recognized before the human immunodeficiency virus (HIV-1). Associated diseases of HTLV-I infection, including a particular kind of leukemia or the development of a specific demyelinating disease, have also been observed. Screening of blood donors for antibodies to HTLV was mandated in November of 1988. This paper examines the biology of HTLV-I and HTLV-II and reviews the testing methods for HTLV-I/II. Data from 39,908 blood donations of volunteer donors at The University of Texas M. D. Anderson Cancer Center (UTMDACC), Division of Laboratory Medicine, Section of Transfusion Medicine are presented. Initially reactive specimens for HTLV antibodies were 158 (0.4 percent). Of these 0.26 percent or 105 of 39,908 were repeatedly reactive. Eight hundred and sixty-seven cancer patients were also tested for HTLV antibodies. Eight or 0.9 percent were repeatedly reactive for HTLV antibodies by enzyme immunoassays (EIA), but only one could be confirmed as positive. HTLV-I/II has a very low incidence in the ambulatory population. The relationship of clinical sequelae and the rate of transmission of these viruses remain unclear. A readily applicable confirmatory test is not yet available. Even significant improvements in the sensitivity and specificity of testing will present ongoing problems for identification of true HTLV carriers. The clinical decision-making process related to the meaning of these results continues to be difficult.