Pathogen-reduced platelets in pediatric and neonatal patients: Demographics, transfusion rates, and transfusion reactions.

BACKGROUND: Pathogen-reduced platelets (PR PLT) are the emerging standard for proactive transfusion-transmitted infection (TTI) mitigation. There is, however, continued hesitation to transfuse PR PLT in children due to limited published data. We report demographics, rates of transfusion, and transfusion reactions (TR) associated with FDA-approved PR PLT in pediatric and neonatal patients at an academic medical center. METHODS: Retrospective review was performed for patients <18 years receiving at least one platelet over a 300-day period at a large, tertiary care hospital. Patients were transfused PR or conventional (CONV) PLT, based on inventory availability. Statistical analysis was performed using Fisher Exact Test. RESULTS: During the study period, 191 patients received 1010 platelet transfusions (892 units). Sixty-eight patients received PR PLT only (1.3 units/patient, 95% confidence interval [CI] 1.1-1.5; 1.8 transfusions/patient, 95% CI 1.4-2.2), and 56 patients received CONV PLT only (1.4 units/patient, 95% CI 1.1-1.7; 1.6 transfusions/patient, 95% CI 1.3-1.9). Patients with hematologic malignancies undergoing chemotherapy/radiation and allogeneic hematopoietic stem cell transplant received the most platelet transfusions and more commonly received both platelet types. Of 506 PR PLT units, 5 TRs occurred; 386 CONV PLT resulted in two TRs (p = .7052). Of 51 neonates, 37 received PR PLT without adverse events, including 13 receiving phototherapy. No TTIs were identified in any group. CONCLUSION: There was no significant difference in rates of transfusion or TRs between PR and CONV PLT. Our study provides additional evidence that PR PLT can be transfused to pediatric and neonatal patients without increasing the risk of acute adverse events.

A pilot study of stored low titer group O whole blood + component therapy versus component therapy only for civilian trauma patients.

BACKGROUND: This pilot assessed transfusion requirements during resuscitation with whole blood followed by standard component therapy (CT) versus CT alone, during a change in practice at a large urban Level I trauma center. METHODS: This was a single-center prospective cohort pilot study. Male trauma patients received up to 4 units of cold-stored low anti-A, anti-B group O whole blood (LTOWB) as initial resuscitation followed by CT as needed (LTOWB + CT). A control group consisting of women and men who presented when LTOWB was unavailable, received CT only (CT group). Exclusion criteria included antiplatelet or anticoagulant medication and death within 24 hours. The primary outcome was total transfusion volume at 24 hours. Secondary outcomes were mortality, morbidity, and intensive care unit- and hospital-free days. RESULTS: Thirty-eight patients received LTOWB, with a median of 2.0 (interquartile range [IQR] 1.0-3.0) units of LTOWB transfused. Thirty-two patients received CT only. At 24 hours after presentation, the LTOWB +CT group had received a median of 2,138 mL (IQR, 1,275-3,325 mL) of all blood products. The median for the CT group was 4,225 mL (IQR, 1,900-5,425 mL; p = 0.06) in unadjusted analysis. When adjusted for Injury Severity Score, sex, and positive Focused Assessment with Sonography for Trauma, LTOWB +CT group patients received 3307 mL of blood products, and CT group patients received 3,260 mL in the first 24 hours (p = 0.95). The adjusted median ratio of plasma to red cells transfused was higher in the LTOWB + CT group (0.85 vs. 0.63 at 24 hours after admission; p = 0.043. Adjusted mortality was 4.4% in the LTOWB + CT group, and 11.7% in the CT group (p = 0.19), with similar complications, intensive care unit-, and hospital-free days in both groups. CONCLUSION: Beginning resuscitation with LTOWB results in equivalent outcomes compared with resuscitation with CT only. LEVEL OF EVIDENCE: Therapeutic (Prospective study with 1 negative criterion, limited control of confounding factors), level III.

Electronic patient identification for sample labeling reduces wrong blood in tube errors.

BACKGROUND: Wrong blood in tube (WBIT) errors are a preventable cause of ABO-mismatched RBC transfusions. Electronic patient identification systems (e.g., scanning a patient's wristband barcode before pretransfusion sample collection) are thought to reduce WBIT errors, but the effectiveness of these systems is unclear. STUDY DESIGN AND METHODS: Part 1: Using retrospective data, we compared pretransfusion sample WBIT rates at hospitals using manual patient identification (n = 16 sites; >1.6 million samples) with WBIT rates at hospitals using electronic patient identification for some or all sample collections (n = 4 sites; >0.5 million samples). Also, we compared WBIT rates after implementation of electronic patient identification with preimplementation WBIT rates. Causes and frequencies of WBIT errors were evaluated at each site. Part 2: Transfusion service laboratories (n = 18) prospectively typed mislabeled (rejected) samples (n = 2844) to determine WBIT rates among samples with minor labeling errors. RESULTS: Part 1: The overall unadjusted WBIT rate at sites using manual patient identification was 1:10,110 versus 1:35,806 for sites using electronic identification (p < 0.0001). Correcting for repeat samples and silent WBIT errors yielded overall adjusted WBIT rates of 1:3046 for sites using manual identification and 1:14,606 for sites using electronic identification (p < 0.0001), with wide variation among individual sites. Part 2: The unadjusted WBIT rate among mislabeled (rejected) samples was 1:71 (adjusted WBIT rate, 1:28). CONCLUSION: In this study, using electronic patient identification at the time of pretransfusion sample collection was associated with approximately fivefold fewer WBIT errors compared with using manual patient identification. WBIT rates were high among mislabeled (rejected) samples, confirming that rejecting samples with even minor labeling errors helps mitigate the risk of ABO-incompatible transfusions.

Red Blood Cell Transfusions Following Resection of Skull Base Meningiomas: Risk Factors and Clinical Outcomes.

Objective This article identifies risk factors for and investigates clinical outcomes of postoperative red blood cell transfusion in patients with skull base meningiomas. Design Retrospective cohort study. Setting Single academic medical center. Participants The transfusion group included patients who had skull base meningiomas and who received packed red blood cell (RBC) transfusion within 7 days of surgery. The no transfusion group included patients who had skull base meningiomas but who did not have RBCs transfused within 7 days of surgery. Main Outcome Measures In-hospital complication rate, length of stay (LOS), and discharge disposition. Results One hundred and ninety-six patients had a craniotomy for resection of a meningioma at our institution from March 2013 to January 2017. Seven patients had skull base meningiomas and received RBC transfusion within 7 days of surgery (the transfusion group). The skull base was an independent risk factor for transfusion after we controlled for the effect of meningioma size (OR 3.89, 95% CI 1.34, 11.25). Operative time greater than 10 hours was an independent risk factor for prolonged hospital stay (OR 8.84, 95% CI 1.08, 72.10) once we controlled for the effect of transfusion. In contrast, transfusion did not independently impact LOS or discharge disposition once we controlled for the effect of operative time. Conclusions The skull base is an independent predictor of RBC transfusion. However, RBC transfusion alone cannot predict LOS or discharge disposition in patients who undergo surgical resection of a skull base meningioma.

Restrictive transfusion threshold is safe in high-risk patients undergoing brain tumor surgery.

OBJECTIVE: To assess the safety of a restrictive threshold for the transfusion of red blood cells (RBCs) compared to a liberal threshold in high-risk patients undergoing brain tumor surgery. PATIENTS AND METHODS: We reviewed patients who were 50 years of age or older with a preoperative American Society of Anesthesiologists physical status class II to V who underwent open craniotomy for tumor resection and were transfused packed RBCs during or after surgery. We retrospectively assigned patients to a restrictive-threshold (a pretransfusion hemoglobin level <8g/dL) or a liberal-threshold group (a pretransfusion hemoglobin level of 8-10/dL). The primary outcome was in-hospital mortality rate. Secondary outcomes were in-hospital complication rates, length of stay, and discharge disposition. RESULTS: Twenty-five patients were included in the study, of which 17 were assigned to a restrictive-threshold group and 8 patients to a liberal-threshold group. The in-hospital mortality rates were 12% for the restrictive-threshold group (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.07-12.11) and 13% for the liberal-threshold group. The in-hospital complication rates were 52.9% for the restrictive-threshold group (OR 1.13, 95% CI 0.21-6.05) and 50% for the liberal-threshold group. The average number of days in the intensive care unit and hospital were 8.6 and 22.4 days in the restrictive-threshold group and 6 and 15 days in the liberal-threshold group, respectively (P=0.69 and P=0.20). The rates of non-routine discharge were 71% in the restrictive-threshold group (OR 2.40, 95% CI 0.42-13.60) and 50% in the liberal-threshold group. CONCLUSIONS: A restrictive transfusion threshold did not significantly influence in-hospital mortality or complication rates, length of stay, or discharge disposition in patients at high operative risk.

Leukocyte filtration lesion impairs functional coagulation in banked whole blood.

BACKGROUND: Whole blood (WB) transfusion is a promising alternative to component therapy in hemostatic resuscitation. Use of banked WB requires filtration of white blood cells (leukoreduction) and an established shelf life during which WB retains coagulant capacities. The goal of this study was to define the time course of coagulation stability in leukoreduced compared to unfiltered WB under standard refrigeration conditions. METHODS: Twelve WB units were donated by healthy volunteers after routine screening. Five units underwent standard leukocyte filtration and five did not. Two units were aliquoted into filtered and unfiltered samples, with platelets added to each sample on day 14. Units were stored at 4°C and sampled on days 0, 1, 2, 3, 4, 5, 6, 7, 10, 14, 21, 28, and 35 for immediate thromboelastography (TEG) analysis, and centrifuged and stored at -80°C for later calibrated automated thrombogram and coagulation factor assays. RESULTS: K-dependent factors and fibrinogen were low normal, decreased slightly over 35 days and were similar between unfiltered and filtered units. Labile factors were better preserved in filtered units, although unfiltered units did not show impaired coagulation over 35 days. Filtered blood had delayed clot initiation on days 0, 1, and 2 as measured by TEG R (p < 0.021); slower clot progression (TEG α-angle) on days 0, 1, 2, 3, 4, 5, and 6 (p < 0.023); weaker final clot (TEG MA) on all days (p < 0.0001). Thrombin generation was delayed on day 28 (p = 0.046) and decreased on days 10, 21, 28, and 35 (p < 0.034). Addition of platelets to filtered WB rescued TEG MA. CONCLUSION: Filtered WB had decreased functional clotting capacity and thrombin generation and may not be suitable for hemostatic resuscitation as the sole blood product. LEVEL OF EVIDENCE: Therapeutic, level IV.

Prevalence of Medical Conditions Potentially Amenable to Cellular Therapy among Families Privately Storing Umbilical Cord Blood.

Introduction Little is known about the prevalence of conditions potentially amenable to cellular therapy among families storing umbilical cord blood in private cord blood banks. Methods A cross-sectional study of families with at least one child who stored umbilical cord blood in the largest private cord blood bank in the United States was performed. Respondent families completed a questionnaire to determine whether children with stored cord blood or a first-degree relative had one or more of 16 conditions amenable primarily to allogeneic stem cell transplant ("transplant indications") or 16 conditions under investigation for autologous stem cell infusion ("regenerative indications"), regardless of whether they received a transplant or infusion. Results 94,803 families responded, representing 33.3 % of those surveyed. Of respondent families, 16.01 % indicated at least one specified condition. 1.64 % reported at least one first-degree member with a transplant indication potentially treatable with an allogeneic stem cell transplant. The most common transplant indications reported among first-degree family members were Non-Hodgkin's Lymphoma (0.33 %), Hodgkin's Lymphoma (0.30 %), and Acute Lymphoblastic Leukemia (0.28 %). 4.23 % reported at least one child with a regenerative indication potentially treatable with an autologous stem cell infusion. The most common regenerative indications among children with stored umbilical cord blood were Autism/Autism Spectrum Disorder/Apraxia (1.93 %), Other Developmental Delay (1.36 %), and Congenital Heart Defect (0.87 %). Discussion Among families storing umbilical cord blood in private cord blood banks, conditions for which stem cell transplant or infusion may be indicated, or are under investigation, appear to be prevalent, especially for regenerative medicine indications.

Survival after ultramassive transfusion: a review of 1360 cases.

BACKGROUND: Information about patient survival after transfusion of multiple blood volumes is limited, and most reports have focused on trauma patients. STUDY DESIGN AND METHODS: Retrospective study of blood use and survival at 11 hospitals in six nations between 2009 and 2013. Ultramassive transfusion (UMT) was defined as transfusion of 20 or more red blood cell (RBC) units over the course of any 2 consecutive calendar days. RESULTS: A total of 1975 patients received UMT and a representative sample of 1360 patients was studied in detail. Patients were grouped into seven diagnostic categories: solid organ transplantation (n = 411), cardiac or major vascular surgery (n = 317), general surgery (n = 228), trauma (n = 221), general medicine (n = 124), obstetrics (n = 23), and other (n = 36). During the 7 days after initiation of UMT, these patients used more than 120,000 blood components. The median (interquartile range) blood use was 35 (26-50) RBC units, 30 (20-47) plasma units, and 7 (4-13) platelet doses. Five- and 30-day survival significantly declined with increasing RBC use. Overall survivals of patients receiving UMT were 71% (5 day) and 60% (30 day), and in the subset of 165 patients receiving 60 or more RBC units over 2 consecutive days, 5-day survival was 54% ranging from 17% (trauma) to 75% (solid organ transplant). The decline in survival with increasing RBC transfusions was minimal for patients undergoing solid organ transplantation and was most pronounced for trauma and nonsurgical bleeding patients. CONCLUSION: Trauma was not the leading cause of UMT. Increasing RBC requirements were significantly associated with decreasing survival. However, survival was more strongly associated with diagnostic category than total RBCs transfused, with highest survival rates in solid organ transplant surgery.

Optimization of human mesenchymal stem cell manufacturing: the effects of animal/xeno-free media.

Due to their immunosuppressive properties, mesenchymal stem cells (MSC) have been evaluated for the treatment of immunological diseases. However, the animal-derived growth supplements utilized for MSC manufacturing may lead to clinical complications. Characterization of alternative media formulations is imperative for MSC therapeutic application. Human BMMSC and AdMSC were expanded in media supplemented with either human platelet lysates (HPL), serum-free media/xeno-free FDA-approved culture medium (SFM/XF), or fetal bovine serum (FBS) and the effects on their properties were investigated. The immunophenotype of resting and IFN-γ primed BMMSC and AdMSC remained unaltered in all media. Both HPL and SFM/XF increased the proliferation of BMMSC and AdMSC. Expansion of BMMSC and AdMSC in HPL increased their differentiation, compared to SFM/XF and FBS. Resting BMMSC and AdMSC, expanded in FBS or SFM/XF, demonstrated potent immunosuppressive properties in both non-primed and IFN-γ primed conditions, whereas HPL-expanded MSC exhibited diminished immunosuppressive properties. Finally, IFN-γ primed BMMSC and AdMSC expanded in SFM/XF and HPL expressed attenuated levels of IDO-1 compared to FBS. Herein, we provide strong evidence supporting the use of the FDA-approved SFM/XF medium, in contrast to the HPL medium, for the expansion of MSC towards therapeutic applications.

Low frequency of anti-D alloimmunization following D+ platelet transfusion: the Anti-D Alloimmunization after D-incompatible Platelet Transfusions (ADAPT) study.

The reported frequency of D alloimmunization in D- recipients after transfusion of D+ platelets varies. This study was designed to determine the frequency of D alloimmunization, previously reported to be an average of 5 ± 2%. A primary anti-D immune response was defined as the detection of anti-D ≥ 28 d following the first D+ platelet transfusion. Data were collected on 485 D- recipients of D+ platelets in 11 centres between 2010 and 2012. Their median age was 60 (range 2-100) years. Diagnoses included: haematological (203/485, 42%), oncological (64/485, 13%) and other diseases (218/485, 45%). Only 7/485 (1·44%; 95% CI 0·58-2·97%) recipients had a primary anti-D response after a median serological follow-up of 77 d (range: 28-2111). There were no statistically significant differences between the primary anti-D formers and the other patients, in terms of gender, age, receipt of immunosuppressive therapy, proportion of patients with haematological/oncological diseases, transfusion of whole blood-derived or apheresis platelets or both, and total number of transfused platelet products. This is the largest study with the longest follow-up of D alloimmunization following D+ platelet transfusion. The low frequency of D alloimmunization should be considered when deciding whether to administer Rh Immune Globulin to D- males and D- females without childbearing potential after transfusion of D+ platelets.

The HI-STAR study: resource utilization and costs associated with serologic testing for antibody-positive patients at four United States medical centers.

BACKGROUND: Little is known about how the resource utilization and costs of serologic work ups for positive antibody screens vary across subpopulations based on diagnosis, transfusion history, and serologic testing history. STUDY DESIGN AND METHODS: Detailed data were collected on patient demographics, diagnoses, transfusion history, history of known allo- and autoantibodies, and specific serologic tests performed for 6077 consecutive serologic work ups in 3608 antibody-positive patients between 2009 and 2011 at four US academic medical centers. Direct testing costs were also determined at each site for each serologic test performed to calculate total costs per work up and per patient over the duration of the study. RESULTS: The mean direct cost of serologic testing was $114 per work up and $195 per patient. The mean cost per patient was significantly higher for 12 of 19 diagnostic categories evaluated, including autoimmune hemolytic anemia (mean cost per patient, $1490; p < 0.001), hematologic malignancies ($640, p < 0.001), and transplant recipients ($462, p = 0.019). Patient transfusion and serologic testing characteristics associated with greatest increases in costs included history of a warm autoantibody ($626, p < 0.001) and more than five prior transfusions ($404, p < 0.001). CONCLUSION: Antibody-positive patients with complex diagnoses or transfusion histories require significantly more resources and incur greater cost to assess red blood cell antibody status.

Storage age of transfused red blood cells during liver transplantation and its intraoperative and postoperative effects.

BACKGROUND: Recent studies suggest that the storage age of red blood cells (RBCs) may be associated with morbidity and mortality in surgical patients. We studied perioperative effects of RBC storage age in patients undergoing orthotopic liver transplant (OLT). METHODS: Adult patients who received ≥ 5 U of RBCs during OLT between January 2004 and June 2009 were studied. The subjects were divided into two groups according to the mean storage age of RBCs they received: new or old RBCs (stored ≤ 14 or >14 days, respectively). Effects of storage age of transfused RBCs during OLT on intraoperative potassium (K(+)) concentrations, incidence of hyperkalemia (K(+) ≥ 5.5 mmol/L), postoperative morbidity, and patient and graft survival were studied. RESULTS: The mean serum K(+) concentrations and the incidence of hyperkalemia during OLT were significantly associated with storage age of the RBCs. Logistic analysis showed that storage age of RBCs was an independent risk factor for intraoperative hyperkalemia (odds ratios 1.067-1.085, p < 0.001) in addition to baseline K(+) concentration and units of RBCs transfused. Patient and graft survival and postoperative morbidity including postoperative ventilation, reoperation, acute renal dysfunction defined by the RIFLE criteria was not associated with old RBCs. CONCLUSIONS: Transfusion of RBCs stored for a longer time was associated with intraoperative hyperkalemia but not with postoperative adverse outcomes in adult OLT. Prevention and treatment of potentially harmful hyperkalemia should be considered when old RBCs are administered.

ABO blood type-incompatible kidney transplantation and access to organs.

OBJECTIVE: To determine whether ABO-incompatible (ABOi) kidney transplantation can be performed safely and result in acceptable posttransplantation outcomes. DESIGN: Prospective study. SETTING: Transplantation center. PATIENTS: In the 1½ years of a new program, 18 patients with renal failure and an ABOi living kidney donor were included in the study. All donors and recipients were of incompatible blood types and underwent transplantation beginning in June 2008. INTERVENTIONS: Patients received immunomodulation (anti-CD20 antibody, intravenous immunoglobulin, and plasmapheresis) until an acceptable isoagglutinin titer was obtained on the date of transplantation. All the kidneys were transplanted heterotopically, and all the patients received induction immunosuppression followed by a combination of prednisone, mycophenolate mofetil, and tacrolimus. Isoagglutinin titers were monitored, and postoperative plasmapheresis was initiated if titers increased. MAIN OUTCOME MEASURES: Patient and allograft survival; length of stay; 1-, 3-, and 6-month and 1-year renal function; and incidence of rejection. RESULTS: Patient survival was 100%, with allograft survival of 94.4%. Mean (SD) length of stay was 6.9 (1.9) days. Donor to recipient transplantation was A to O in 11 cases, A2 to B in 1, B to A in 3, B to O in 1, and AB to B in 2. Mean (SD) creatinine levels, a measure of graft function, were 1.2 (0.5) mg/dL at discharge, 1.4 (0.4) mg/dL at 1 month, 1.3 (0.45) mg/dL at 3 months, 1.1 (0.3) mg/dL at 6 months, and 1.2 (0.2) mg/dL at 1 year. One episode of cellular rejection occurred. CONCLUSIONS: These short-term results suggest that with a straightforward regimen, ABOi kidney transplantation is possible, acceptable results and graft function are obtainable, and access to kidney transplantation for those with a blood type-incompatible donor can be expanded.

Increased all-cause and cancer mortality in HTLV-II infection.

BACKGROUND: Human T-lymphotropic virus (HTLV)-I and HTLV-II cause chronic human retroviral infections, but few studies have examined the impact of either virus on survival among otherwise healthy individuals. The authors analyzed all-cause and cancer mortality in a prospective cohort of 155 HTLV-I, 387 HTLV-II, and 799 seronegative subjects. METHODS: Vital status was ascertained using death certificates, the US Social Security Death Index or family report, and causes of death were grouped into 9 categories. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models. RESULTS: After a median follow-up of 15.9 years, there were 105 deaths: 22 HTLV-I, 41 HTLV-II, and 42 HTLV-seronegative. Cancer was the predominant cause of death, resulting in 8 HTLV-I, 17 HTLV-II, and 15 HTLV-seronegative deaths. After adjustment for confounding, HTLV-I status was not significantly associated with increased all-cause mortality, though there was a positive trend (HR: 1.6, 95% CI: 0.8 to 3.1). HTLV-II status was strongly associated with increased all-cause (HR: 2.4, 95% CI: 1.4 to 4.4) and cancer mortality (HR: 3.8, 95% CI: 1.6 to 9.2). CONCLUSIONS: The observed associations of HTLV-II with all-cause and cancer mortality could reflect biological effects of HTLV-II infection, residual confounding by socioeconomic status or other factors, or differential access to health care and cancer screening.

A severe case of atypical hemolytic uremic syndrome associated with pneumococcal infection and T activation treated successfully with plasma exchange.

BACKGROUND: A severe nondiarrheal form of hemolytic uremic syndrome in children is associated with pneumococcal infection (pHUS). Neuraminidase released by the pneumococci may cleave N-acetylneuraminic acid residues on red blood cells (RBCs), leading to the exposure of the T cryptantigen and polyagglutinability of RBCs, a process known as T activation. Data suggest a pathogenic role of exposed T antigens on glomeruli interacting with naturally occurring anti-T in the development of renal dysfunction in pHUS. By reducing the levels of anti-T and neuraminidase, plasma exchange (PE) may have a role in the treatment of severe cases of pHUS. CASE REPORT: A previously healthy 2-year-old boy presented with acute renal failure, thrombocytopenia, microangiopathic hemolytic anemia, pneumococcal infection, and T activation of RBCs. A diagnosis of pHUS was made. Due to rapid clinical decline, daily single-volume PE with 5 percent albumin replacement was initiated. Infusion of additional plasma was avoided by using only saline-washed RBCs for transfusion. He made a full recovery after 13 PEs and remained well at follow-up 7 months later. RESULTS: Polyagglutinability of RBCs was shown by mixing patient RBCs with five normal donor sera. The agglutination assays with a panel of lectins confirmed the specificity of exposed T antigen as the cause of polyagglutinability. CONCLUSION: The dramatic response seen in this patient suggests that PE utilizing albumin replacement may benefit patients with severe pHUS.

Nearly two decades using the check-type to prevent ABO incompatible transfusions: one institution's experience.

To detect miscollected (wrong blood in tube [WBIT]) samples, our institution requires a second independently drawn sample (check-type [CT]) on previously untyped, non-group O patients who are likely to require transfusion. During the 17-year period addressed by this report, 94 WBIT errors were detected: 57% by comparison with a historic blood type, 7% by the CT, and 35% by other means. The CT averted 5 potential ABO-incompatible transfusions. Our corrected WBIT error rate is 1 in 3,713 for verified samples tested between 2000 and 2003, the period for which actual number of CTs performed was available. The estimated rate of WBIT for the 17-year period is 1 in 2,262 samples. ABO-incompatible transfusions due to WBIT-type errors are avoided by comparison of current blood type results with a historic type, and the CT is an effective way to create a historic type.