R O Gilcher

University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States

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Publications (25)229.33 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The Oklahoma Thrombotic ThrombocytopenicPurpura-Hemolytic Uremic Syndrome (TTP-HUS) Registry has enrolled all 335 consecutive patients from central, western and southeastern Oklahoma who had their first episode of clinically diagnosed TTP or HUS from 1989 through 2005; follow-up is complete for 333 patients. Identifying all patients is possible since plasma exchange is the essential treatment for all adults and some children with these disorders and since the Oklahoma Blood Institute (OBI) is the sole provider of plasma exchange services for this region. Patients in the Oklahoma TTP-HUS Registry have come from 46 counties and have been treated in 16 hospitals; 227 physicians have provided the principal care for these patients. A support group formed in 1996 has met 3 times each year, averaging 17 former patients plus 16 additional family members and friends. Registry data are an important source of information for physicians and their patients, providing a complete community perspective of these uncommon disorders.
    The Journal of the Oklahoma State Medical Association 08/2007; 100(7):273-8.
  • James W Smith, Ronald O Gilcher
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    ABSTRACT: Automated red blood cell (RBC) collection is a newer but well-established form of donor apheresis. The technologies comprising and supporting apheresis have undergone significant advancements through the past 50 years, and we anticipate further improvements in devices and systems for automated RBC collection. Multiple factors must be considered in implementing automated RBC collections, but these procedures provide a way to draw additional RBC products that meet cGMP, regulatory, blood collector economic and donor objectives while maintaining or improving RBC availability. The continuing need for RBCs, accompanied by shrinking donor availability, would indicate that automated RBC collections will grow.
    Transfusion and Apheresis Science 05/2006; 34(2):219-26. · 1.23 Impact Factor
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    ABSTRACT: To prevent donor loss and improve retention, it is important to understand the major deterrents to blood donation and to identify factors that can be effectively addressed by blood centers. A 30-item self-administered questionnaire was completed in 2003 by 1705 first-time and 2437 repeat US donors who had not donated in 2 to 3 years. Asian, Hispanic, black, and white first-time and repeat donors rated the importance of deterrents to donation in their decision to not return with a 1 to 5 scale. Categorical analysis of variance methods were used to compare the importance of deterrents between first-time and repeat donors of different race or ethnicity. Not having a convenient place to donate was most commonly cited as an important or very important reason for not returning by 32 to 42 percent of first-time and 26 to 43 percent of repeat respondents. Although bad treatment and poor staff skills were less of a barrier than convenience, they were more important for minority donors. Other factors such as physical side effects, foreign travel, or length of the process appeared less important. Inconvenience is a major barrier to donating, suggesting that mobile collections and increased hours of operation might help recapture lapsed donors. The finding that lapsed minority donors were more likely to give bad treatment and poor staff skills as important reasons to not donate is disconcerting in light of the changing donor demographics and increased efforts to recruit these donors.
    Transfusion 05/2006; 46(4):545-53. · 3.53 Impact Factor
  • Ronald O Gilcher, Suzanne McCombs
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    ABSTRACT: This review is designed to help readers understand seasonal blood shortages and provide solutions through the use of technology that can increase the number of red blood cell units collected and the use of recruitment and marketing initiatives that appeal to the increasingly diverse donor base. Seasonal shortages are, in reality, mostly shortages of group O red blood cells and occur most commonly during midsummer and early winter. The shortages occur primarily from increased use of group O red blood cells at times of decreased donor availability. While reducing the disproportionate use of red cells will help, blood centers can more quickly reduce the seasonal deficits by using automated red cell technology to collect double red blood cell units; targeted marketing programs to provide effective messages; seasonal advertising campaigns; and recognition, benefits, and incentives to enhance the donor motivation donation threshold. A multi-level approach to increasing blood donations at difficult times of the year can ensure that donations are increased at a time when regular donor availability is decreased. Seasonal blood shortages can be eliminated by understanding the nature of the shortages, why and when they occur, and using more sophisticated recruitment and marketing strategies as well as automated collection technologies to enhance the blood supply.
    Current Opinion in Hematology 12/2005; 12(6):503-8. · 4.11 Impact Factor
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    ABSTRACT: Background and Objectives  Converting first-time donors to become regular donors continues to be a challenge facing blood centres. We examined whether first-time donors with frequent return in the first 12 months were more likely to become regular donors.Subjects and Methods  The donation histories of 179 409 community whole-blood donors, whose first-time donation in 1991 was negative on donor screening tests, were evaluated. Donors were categorized by the number of donations made in the 12 months after (and including) their first donation. The donor return pattern in the subsequent 6 years, and its association with first-year donation frequency and demographics, was evaluated by using logistic regression analysis. A ‘regular donor’ was defined as one who returned to donate in at least 4 of the 6 years of follow-up.Results  First-year donation frequency was significantly correlated with long-term donor return (P < 0·0001). Among those giving 1, 2, 3, 4 and ≥ 5 donations in the first year, 4%, 11%, 21%, 32% and 42%, respectively, became regular donors (P < 0·0001). Similar associations between donation pattern and donor return behaviour were observed after adjusting for demographic variables (P < 0·0001).Conclusions  Strategies aimed at encouraging current donors to donate more frequently during the first year may help to establish a regular donation behaviour.
    Vox Sanguinis 01/2005; 88(2):114 - 121. · 2.85 Impact Factor
  • Ronald O Gilcher
    Transfusion 01/2004; 43(12):1658-60. · 3.53 Impact Factor
  • Transfusion 02/2003; 35(11):944 - 951. · 3.53 Impact Factor
  • James W Smith, Jean E Forsberg, Ronald O Gilcher
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    ABSTRACT: Blood donor screening and blood collection are two of the donor-focused activities inherent in the process of maintaining an adequate blood supply. Donor screening represents procedures to provide safety for both donors as well as recipients. Donor medical history questions are so cumbersome that self-administered manual, computer-assisted, or on-line donor questions are under consideration in order to reduce time involved in the screening process. Blood collection procedures remain primarily based on whole blood donations, but apheresis donations are increasing steadily. The yield of multiple transfusible units per donation, as well as quality and reproducibility per product, support the use of apheresis procedures or other automated whole blood techniques to help offset blood shortages.
    Current hematology reports 12/2002; 1(2):129-33.
  • New England Journal of Medicine 11/2002; 347(14):1075-8. · 54.42 Impact Factor
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    ABSTRACT: BACKGROUND: With the increased frequency of diagnosis and improved survival of thrombotic thrombocytopenic purpura-hemolytic-uremic syndrome (TTP-HUS), the morbidity of plasma exchange (PE) treatment has become more important.STUDY DESIGN AND METHODS: Data were prospectively collected on 71 consecutive patients referred to the Oklahoma Blood Institute (OBI) for PE treatment for clinically suspected TTP-HUS from mid-1996 to mid-1999. Complications were defined as major or minor, and distinguished between those related to central venous catheter access or to the plasma.RESULTS: Twenty-one patients (30%) had 27 major complications, which caused two deaths. The major complications included 2 episodes of hemorrhage after subclavian line insertion (1 death), 1 pneumothorax requiring a chest tube, 12 systemic infections (1 death), 7 episodes of catheter thrombosis requiring removal of the central venous catheter, 2 episodes of venous thrombosis requiring anticoagulant treatment, 2 episodes of hypoxemia and hypotension, and 1 episode of serum sickness. Minor complications occurred in 22 additional patients (31%). Twenty-eight patients (39%) had no complications.CONCLUSIONS: The morbidity and mortality of catheter placement and PE are important considerations when PE treatment for clinically suspected TTP-HUS is anticipated.
    Transfusion 04/2002; 40(8):896 - 901. · 3.53 Impact Factor
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    ABSTRACT: Despite changes in eligibility policies, practical barriers limit blood donations from individuals with hemochromatosis. Increased knowledge of hemochromatosis donor characteristics may help foster further changes that will promote more donations. To estimate the prevalence of donors diagnosed as having hemochromatosis and to compare rates of unreported deferrable risks for transfusion-transmissible viral infections (TTVIs), positive screening test results for TTVIs, and donation patterns between hemochromatosis patient donors and donors reporting no medical conditions necessitating phlebotomy (non-health-related donors). An anonymous mail survey conducted in 1998 as part of the ongoing Retrovirus Epidemiology Donor Study. Among a stratified probability sample of 92 581 blood donors from 8 geographically diverse US blood centers, 52 650 (57%) responded. Prevalence of hemochromatosis among blood donors; prevalence of unreported deferrable risks and positive screening test results for TTVIs among hemochromatosis patient donors vs non-health-related donors. One hundred ninety-seven respondents (0.4%) identified themselves as hemochromatosis patients and 50 079 (95.1%) as non-health-related donors. An estimated 0.8% of all donations were from hemochromatosis patients, 45.8% of whom reported that they had donated blood to treat their illness. The proportion of repeat donors was higher in hemochromatosis patients than in non-health-related donors (83.5% vs 76.5%; P =.03). Among repeat donors, 68.7% of hemochromatosis patients reported donating at least 3 times in the past year compared with 49.1% of non-health-related donors (P<.001). The prevalence of unreported deferrable risks for TTVIs was similar in hemochromatosis patients (2.0%) and non-health-related donors(3.1%) as was the overall prevalence of positive screening test results (1.3% of hemochromatosis patients vs 1.6% of non-health-related donors). Although significant numbers of hemochromatosis patients reported donating blood for therapeutic reasons, our findings suggest that this population does not present a greater risk to blood safety than other donors.
    JAMA The Journal of the American Medical Association 09/2001; 286(12):1475-81. · 29.98 Impact Factor
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    ABSTRACT: Therapeutic plasmapheresis may remove platelets as well as plasma. Unintentional platelet loss, if not recognized, may lead to inappropriate patient assessment and treatment. A patient with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is reported in whom persistent thrombocytopenia was interpreted as continuing active disease; thrombocytopenia resolved only after plasma exchange treatments were stopped. This observation prompted a systematic study of platelet loss with plasmapheresis. Data are reported on platelet loss during 432 apheresis procedures in 71 patients with six disease categories using three different instruments. Comparing the first procedure recorded for each patient, there was a significant difference among instrument types (P<0.001); platelet loss was greater with the Fresenius AS 104 (17.5%, N = 21) than with the COBE Spectra (1.6%, N = 26) or the Haemonetics LN9000 (2.6%, N = 24). With all procedures, platelet loss ranged from 0 to 71%. Among disease categories, platelet loss was greater in patients with dysproteinemias who were treated for hyperviscosity symptoms. Absolute platelet loss with the first recorded apheresis procedure, in the 34 patients who had a normal platelet count before the procedure, was also greater with the AS 104 (2.23 x 10(11) platelets) than with the Spectra (0.29 x 10(11) platelets) or the LN9000 (0.37 x 10(11) platelets). In 39 patients in whom data were collected on consecutive days, platelet removal by plasmapheresis correlated with a decreased patient platelet count (r = 0.40, P = 0.011). In these 39 patients, the platelet counts were significantly decreased at 24 hours (P = 0.002).
    Journal of Clinical Apheresis 02/2001; 16(2):55-60. · 2.27 Impact Factor
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    ABSTRACT: Context Despite changes in eligibility policies, practical barriers limit blood donations from individuals with hemochromatosis. Increased knowledge of hemochromatosis donor characteristics may help foster further changes that will promote more donations.Objectives To estimate the prevalence of donors diagnosed as having hemochromatosis and to compare rates of unreported deferrable risks for transfusion-transmissible viral infections (TTVIs), positive screening test results for TTVIs, and donation patterns between hemochromatosis patient donors and donors reporting no medical conditions necessitating phlebotomy (non–health-related donors).Design An anonymous mail survey conducted in 1998 as part of the ongoing Retrovirus Epidemiology Donor Study.Setting and Participants Among a stratified probability sample of 92 581 blood donors from 8 geographically diverse US blood centers, 52 650 (57%) responded.Main Outcome Measures Prevalence of hemochromatosis among blood donors; prevalence of unreported deferrable risks and positive screening test results for TTVIs among hemochromatosis patient donors vs non–health-related donors.Results One hundred ninety-seven respondents (0.4%) identified themselves as hemochromatosis patients and 50 079 (95.1%) as non–health-related donors. An estimated 0.8% of all donations were from hemochromatosis patients, 45.8% of whom reported that they had donated blood to treat their illness. The proportion of repeat donors was higher in hemochromatosis patients than in non–health-related donors (83.5% vs 76.5%; P = .03). Among repeat donors, 68.7% of hemochromatosis patients reported donating at least 3 times in the past year compared with 49.1% of non–health-related donors (P<.001). The prevalence of unreported deferrable risks for TTVIs was similar in hemochromatosis patients (2.0%) and non–health-related donors(3.1%) as was the overall prevalence of positive screening test results (1.3% of hemochromatosis patients vs 1.6% of non–health-related donors).Conclusions Although significant numbers of hemochromatosis patients reported donating blood for therapeutic reasons, our findings suggest that this population does not present a greater risk to blood safety than other donors. Figures in this Article Hereditary hemochromatosis is an autosomal recessive disorder of iron metabolism characterized by an increase in iron absorption from the gastrointestinal tract, which can lead to the accumulation of iron in multiple organs and tissues.1- 2 Although once believed to be rare, with current genetic advances, hemochromatosis is now widely recognized as a common condition.3- 5 Among white people living in the United States, the prevalence is estimated at 0.5%.6 If untreated, hemochromatosis can result in the development of hepatic cirrhosis, hepatocellular carcinoma, cardiac failure, diabetes mellitus, arthritis, and premature death.1- 2 Most clinical complications can be avoided if the disorder is identified early and is treated with periodic phlebotomies to facilitate iron unloading from critical organs.2,7- 10 Management commonly includes the weekly or slightly less frequent removal of 1 to 2 units (450-1000 mL) of blood until iron stores are depleted, then maintenance phlebotomies to regulate iron stores. Men typically require 3 or 4 units and women 1 or 2 units to be removed annually.8 Although there is no known added risk to transfusion recipients of products from hemochromatosis donors,11- 12 the US Food and Drug Administration (FDA) has required and the American Medical Association (AMA) has endorsed13 that blood collected from otherwise healthy hemochromatosis patients be used with some restrictions. The principal concern is the perceived benefits these patients may receive from donating.14- 15 Early research suggests that blood from paid donors is more likely to transmit hepatitis than blood from altruistic volunteer donors.16- 19 This work led to the initiation of an all-volunteer donor system in the 1970s,20 a move that resulted in a significant decrease in the incidence of posttransfusion hepatitis.21 It has been hypothesized that certain incentives might induce some individuals with risk factors for transfusion-transmissible viral infections (TTVIs) to conceal their history to avoid being deferred.22- 23 The deferral of individuals with risk factors is still the principal means of reducing the likelihood of collecting recently acquired infectious donations not detected by laboratory testing.24- 25 The effectiveness of donor screening is suggested by the fact that the prevalence of all major TTVIs in first-time donors, a population that has not been prescreened by laboratory TTVI testing, are considerably lower than in the general population.26 While not receiving payment for donating, hemochromatosis patients may still have a financial incentive for giving. The mean cost of phlebotomy has been estimated at $74 per unit for those with partial or no insurance coverage,27 an expense that could be saved by donating. Because patients with hemochromatosis might benefit medically and financially from giving blood, there is concern that their blood may not be as safe as blood from volunteer donors.13- 15 Although the FDA does not prohibit the use of blood from hemochromatosis patients, it has required that all blood drawn during therapeutic phlebotomies be labeled specifying its source.28 Labeled blood can only be used at the discretion of physicians and their patients; in practice, labeled blood is not well accepted and is usually discarded.15 Food and Drug Administration policies further stipulate that a donor may not give more than 1 unit in 8 weeks without a physician's examination at the time of donation,28 a guideline that limits the potential for collecting blood during initial iron depletion therapy. The AMA advocates that therapeutic units from hemochromatosis patients be labeled until the potential financial inducement to donate can be removed.13 To permit the wider use of hemochromatotic blood, in 1999 the FDA began granting labeling and frequency of collection variances to blood collection organizations that offer no-cost phlebotomies to all patients with hemochromatosis. These variances enable blood to be collected from patients with hemochromatosis without labeling the unit, and if the patient presents a prescription for phlebotomy, a physician is not required to certify the patient's health regardless of when he/she last donated (J. E. Henney, MD, FDA memorandum [Blood Donations by Individuals With Hemochromatosis], August 10, 1999).29 Despite the reduced restrictions, there are still practical barriers limiting the use of hemochromatosis blood. Foremost, collection facilities must be willing to assume the costs associated with providing free therapeutic phlebotomies to those who do not qualify as blood donors. One study of 211 hemochromatosis probands found that 33% would not have met the criteria for blood donation.30 As of May 2001, 15 (10%) of 149 licensed and 3 (0.4%) of 853 registered-only blood collection organizations have applied for and received labeling and frequency of collection variances for hemochromatosis patients (A.E.W., written communication, May 29, 2001). To realize the full benefit of collecting blood from patients with hemochromatosis requires a loosening of restrictions that can be accomplished only through increased understanding of the motivations, risk profiles, and donation behaviors of otherwise healthy patients with hemochromatosis. To our knowledge, this is the first large-scale study to address these questions.
    JAMA The Journal of the American Medical Association 01/2001; 286(12):1475-1481. · 29.98 Impact Factor
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    ABSTRACT: Therapeutic plasmapheresis may remove platelets as well as plasma. Unintentional platelet loss, if not recognized, may lead to inappropriate patient assessment and treatment. A patient with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is reported in whom persistent thrombocytopenia was interpreted as continuing active disease; thrombocytopenia resolved only after plasma exchange treatments were stopped. This observation prompted a systematic study of platelet loss with plasmapheresis. Data are reported on platelet loss during 432 apheresis procedures in 71 patients with six disease categories using three different instruments. Comparing the first procedure recorded for each patient, there was a significant difference among instrument types (P<0.001); platelet loss was greater with the Fresenius AS 104 (17.5%, N = 21) than with the COBE Spectra (1.6%, N = 26) or the Haemonetics LN9000 (2.6%, N = 24). With all procedures, platelet loss ranged from 0 to 71%. Among disease categories, platelet loss was greater in patients with dysproteinemias who were treated for hyperviscosity symptoms. Absolute platelet loss with the first recorded apheresis procedure, in the 34 patients who had a normal platelet count before the procedure, was also greater with the AS 104 (2.23 × 1011 platelets) than with the Spectra (0.29 × 1011 platelets) or the LN9000 (0.37 × 1011 platelets). In 39 patients in whom data were collected on consecutive days, platelet removal by plasmapheresis correlated with a decreased patient platelet count (r = 0.40, P = 0.011). In these 39 patients, the platelet counts were significantly decreased at 24 hours (P = 0.002). J. Clin. Apheresis. 16:55–60, 2001. © 2001 Wiley-Liss, Inc.
    Journal of Clinical Apheresis 12/2000; 16(2):55 - 60. · 2.27 Impact Factor
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    ABSTRACT: With the increased frequency of diagnosis and improved survival of thrombotic thrombocytopenic purpura-hemolytic-uremic syndrome (TTP-HUS), the morbidity of plasma exchange (PE) treatment has become more important. Data were prospectively collected on 71 consecutive patients referred to the Oklahoma Blood Institute (OBI) for PE treatment for clinically suspected TTP-HUS from mid-1996 to mid-1999. Complications were defined as major or minor, and distinguished between those related to central venous catheter access or to the plasma. Twenty-one patients (30%) had 27 major complications, which caused two deaths. The major complications included 2 episodes of hemorrhage after subclavian line insertion (1 death), 1 pneumothorax requiring a chest tube, 12 systemic infections (1 death), 7 episodes of catheter thrombosis requiring removal of the central venous catheter, 2 episodes of venous thrombosis requiring anticoagulant treatment, 2 episodes of hypoxemia and hypotension, and 1 episode of serum sickness. Minor complications occurred in 22 additional patients (31%). Twenty-eight patients (39%) had no complications. The morbidity and mortality of catheter placement and PE are important considerations when PE treatment for clinically suspected TTP-HUS is anticipated.
    Transfusion 09/2000; 40(8):896-901. · 3.53 Impact Factor
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    ABSTRACT: Thrombotic thrombocytopenia purpura (TTP) is perplexing, mainly because of its difficult diagnosis and dramatic clinical presentations, high mortality rates, and the effectiveness of empirical plasma infusions and plasma exchanges. Scientific evidence supports the hypothesis that TTP results from platelet hyperagglutination. To support this, a new in vitro bleeding time (Platelet-Stattrade mark) test was used. Eleven patients had a mean in vitro bleeding time of 7.3 +/- 2.1 seconds prior to plasma exchange and eight patients had a mean of 13.6 +/- 4.7 seconds after the plasma exchange procedure. Normal controls were 14 +/- 2 seconds. The test was used to monitor plasma exchanges in two patients. At the time the platelet count and LDH returned to normal, the Platelet-Stattrade mark remained shortened. The two patients relapsed and required continued plasma exchanges until Platelet-Stattrade mark corrected to normal. These results suggest that plasma exchanges may be effectively monitored by Platelet-Stattrade mark rather than the traditional parameters, i.e., LDH. Therefore, the Platelet-Stattrade mark test may be a useful test to diagnose TTP and monitor therapy in this disease.
    Journal of Clinical Apheresis 02/2000; 15(3):161-8. · 2.27 Impact Factor
  • J W Smith, R O Gilcher
    Transfusion Medicine Reviews 05/1999; 13(2):118-23. · 3.76 Impact Factor
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    ABSTRACT: Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is a clinical syndrome defined by the presence of thrombocytopenia and microangiopathic hemolytic anemia without a clinically apparent etiology. Patients may also have multiple other symptoms and signs including neurologic and renal abnormalities and fever. In the era prior to effective therapy with plasma exchange, most patients developed multisystem abnormalities and the syndrome was more easily recognized. Now, since there is urgency to begin treatment, sufficient diagnostic criteria for TTP-HUS are only thrombocytopenia and microangiopathic hemolytic anemia without a clinically apparent cause; patients may have no neurologic symptoms, renal abnormalities, or fever. This has lead to an apparent increased incidence because of both the increased importance of early recognition and the decreased specificity of the diagnostic criteria. Effective treatment has also revealed new aspects of the clinical course of TTP-HUS following the initial response to plasma exchange treatment: prompt exacerbations, which are common when plasma exchange is diminished in frequency or discontinued, and later relapses, which may occur many years after the initial episode. This review describes the evolution of the syndrome of TTP-HUS in the current era of effective treatment, and describes the management and clinical outcomes among patients treated by the Oklahoma Blood Institute.
    Journal of Clinical Apheresis 02/1998; 13(3):120-5. · 2.27 Impact Factor
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    ABSTRACT: Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is a clinical syndrome defined by the presence of thrombocytopenia and microangiopathic hemolytic anemia without a clinically apparent etiology. Patients may also have multiple other symptoms and signs including neurologic and renal abnormalities and fever. In the era prior to effective therapy with plasma exchange, most patients developed multisystem abnormalities and the syndrome was more easily recognized. Now, since there is urgency to begin treatment, sufficient diagnostic criteria for TTP-HUS are only thrombocytopenia and microangiopathic hemolytic anemia without a clinically apparent cause; patients may have no neurologic symptoms, renal abnormalities, or fever. This has lead to an apparent increased incidence because of both the increased importance of early recognition and the decreased specificity of the diagnostic criteria. Effective treatment has also revealed new aspects of the clinical course of TTP-HUS following the initial response to plasma exchange treatment: prompt exacerbations, which are common when plasma exchange is diminished in frequency or discontinued, and later relapses, which may occur many years after the initial episode. This review describes the evolution of the syndrome of TTP-HUS in the current era of effective treatment, and describes the management and clinical outcomes among patients treated by the Oklahoma Blood Institute. J. Clin. Apheresis 13:120–125, 1998. © 1998 Wiley-Liss, Inc.
    Journal of Clinical Apheresis 12/1997; 13(3):120 - 125. · 2.27 Impact Factor
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    ABSTRACT: Calculations of the incidence of hepatitis B virus (HBV) infections in the blood donor setting that are based solely on data for seroconversion to hepatitis B surface antigen (HBsAg) will underestimate the incidence due to the transient nature of antigenemia. Estimates based on antibody to hepatitis B core antigen will overestimate the incidence due to false-positive results caused by the nonspecificity of the test. Serologic test results were obtained from multiple-time volunteer donors at five United States blood centers from January 1991 through December 1993. The observed HBsAg seroconversion rate was multiplied by an adjustment factor, derived from the weighted average probability of a positive HBsAg test for HBV-infected donors who become chronic carriers, for donors with a primary antibody response without detectable antigenemia, and for donors who develop transient antigenemia. Among 586,507 multiple-time donors giving 2,318,356 donations and observed for 822,426 person-years, the HBsAg incidence rate was 4.01 per 100,000 person-years. On the basis of prior reports of the duration of HBsAg positivity and the observed distribution of interdonation intervals among the study group, there was an estimated 53-percent chance that an HBV-infected donor with transient antigenemia would have a positive HBsAg test result. If 70 percent of newly HBV-infected adults have transient antigenemia, 25 percent have a primary antibody response without primary antigenemia, and 5 percent become chronic carriers, the overall chance of being detected by the HBsAg test was 42 percent, for an adjustment factor of 2.38. The total HBV incidence rate, therefore, was estimated to be 9.54 per 100,000 person-years. The crude HBV incidence rate observed from HBsAg test results will underestimate the true rate. The adjusted HBV incidence rate should be used in applications such as estimations of residual HBV risk to the blood supply and projections of the benefits of screening for HBV DNA.
    Transfusion 07/1997; 37(6):634-40. · 3.53 Impact Factor

Publication Stats

639 Citations
229.33 Total Impact Points

Institutions

  • 2000–2007
    • University of Oklahoma Health Sciences Center
      • Department of Biostatistics and Epidemiology
      Oklahoma City, OK, United States
  • 1997–2006
    • Oklahoma Blood Institute
      Oklahoma City, Oklahoma, United States
  • 2001
    • Westat
      Maryland, United States