Qualitative analysis of Doppler assessment used for surveillance of alloimmunized individuals.

OBJECTIVES: To summarize image quality variables for alloimmunized women at risk for fetal anemia. To investigate the association between image quality with the highest and median middle cerebral artery peak systolic velocity (MCA-PSV) at the last visit and fetal anemia based on hemoglobin. STUDY DESIGN: This study was a qualitative retrospective analysis of 192 Doppler ultrasound images used in the detection of fetal anemia in 26 alloimmunized women seen in a Minneapolis hospital over the past 3 years. Images were graded on seven criteria found in literature. RESULTS: Of the images analyzed, 23 (12.0%) of the 192 met all seven image quality criteria. Using the highest MCA-PSV value, the sensitivity, and specificity were 55.6% and 94.1%, respectively. Using the median MCA-PSV value, the sensitivity, and specificity were 44.4% and 94.1%, respectively. CONCLUSIONS: Only a minority of Doppler images meet all suggested image criteria. This could negatively impact the accuracy of the MCA-PSV measurements as indicated by the decreased sensitivity in our evaluations.

Induced Abortion and the Risk of Rh Sensitization.

Importance: While population-level data suggest Rh immunoglobulin is unnecessary before 12 weeks' gestation, clinical evidence is limited. Thus, guidelines vary, creating confusion surrounding risks and benefits of Rh testing and treatment. As abortion care in traditional clinical settings becomes harder to access, many people are choosing to self-manage and need to know if ancillary blood type testing is necessary. Objective: To determine how frequently maternal exposure to fetal red blood cells (fRBCs) exceeds the most conservative published threshold for Rh sensitization in induced first-trimester abortion. Design, Setting, and Participants: Multicenter, observational, prospective cohort study using high-throughput flow cytometry to detect circulating fRBCs in paired maternal blood samples before and after induced first-trimester abortion (medication or procedural). Individuals undergoing induced first-trimester abortion before 12 weeks 0 days' gestation were included. Paired blood samples were available from 506 participants who underwent either medical (n = 319 [63.0%]) or procedural (n = 187 [37.0%]) abortion. Exposure: Induced first-trimester abortion. Main Outcomes and Measures: The primary outcome was the proportion of participants with fRBC counts above the sensitization threshold (125 fRBCs/5 million total RBCs) after induced first-trimester abortion. Results: Among the 506 participants, the mean (SD) age was 27.4 (5.5) years, 313 (61.9%) were Black, and 123 (24.3%) were White. Three of the 506 participants had elevated fRBC counts at baseline; 1 of these patients had an elevated fRBC count following the abortion (0.2% [95% CI, 0%-0.93%]). No other participants had elevated fRBC counts above the sensitization threshold after induced first-trimester abortion. The median change from baseline was 0 fRBCs, with upper 95th and 99th percentiles of 24 and 35.6 fRBCs, respectively. Although there was a strong association between the preabortion and postabortion fRBC counts, no other baseline characteristic was significantly associated with postabortion fRBC count. Conclusions and Relevance: Induced first-trimester abortion is not a risk factor for Rh sensitization, indicating that Rh testing and treatment are unnecessary before 12 weeks' gestation. This evidence may be used to inform international guidelines for Rh immunoglobulin administration following first-trimester induced abortion.

Following targeted routine antenatal anti-D prophylaxis, almost half of the pregnant women had undetectable anti-D prophylaxis at delivery.

INTRODUCTION: In September 2016, a nationwide targeted routine antenatal anti-D prophylaxis program was implemented in Norway. The prophylaxis (anti-D immunoglobulin) aims to cover the whole third trimester and is administered in gestational week 28 to RhD-negative women who carry RhD-positive fetuses. However, in many women, antibody screening at delivery does not detect anti-D immunoglobulin. The goal of this study was to investigate the presumable role of dose and timing of antenatal anti-D immunoglobulin administration in non-detectable prophylaxis at the time of delivery. MATERIAL AND METHODS: In this retrospective observational study, RhD-negative pregnant women who gave birth at Oslo University Hospital and Akershus University Hospital between January 2017 and December 2019 were analyzed. Women who received antenatal anti-D immunoglobulin (1500 IU at Oslo University Hospital and 1250 IU at Akershus University Hospital) when fetal RHD genotyping at gestational week 24 predicted an RhD-positive fetus were included if an antibody screen at delivery was available. Data from the blood bank, maternity information systems, and electronic patient records were used. RESULTS: Analysis of the 984 RhD-negative women at the two hospitals revealed that 45.4% had non-detectable anti-D at delivery. A significant difference between the two hospitals was observed: 40.5% at Oslo University Hospital (n = 509) and 50.7% at Akershus University Hospital (n = 475) (p = 0.001). The proportion with non-detectable anti-D increased to 56.0 and 75.3%, respectively (p = 0.008) in the group of women who gave birth 12 weeks after routine antenatal anti-D prophylaxis. Significantly fewer women had detectable anti-D at delivery when the lower anti-D immunoglobulin dose (1250 IU) was administered antenatally. Multiple logistic regression indicated that the time interval between routine antenatal anti-D prophylaxis and delivery, in addition to anti-D dose, were significantly associated with detectable anti-D at delivery (p < 0.001). CONCLUSIONS: We do not know which RhD-negative pregnant women, despite antenatal anti-D prophylaxis, are at risk of RhD alloimmunization, when antibody screening is negative at delivery. Administration of antenatal prophylaxis should probably be moved closer to delivery, since the risk of fetomaternal hemorrhage is higher during the last weeks of the third trimester.

Rhesus D alloimmunization in pregnancy from 1996 to 2015 in Iceland: a nation-wide population study prior to routine antenatal anti-D prophylaxis.

BACKGROUND: Rhesus D (RhD) incompatibility is still the most important cause of hemolytic disease of the fetus and newborn (HDFN) worldwide. The aim of this study was to investigate the incidence, causes, and consequences of anti-D alloimmunizations in pregnancy in Iceland, prior to implementation of targeted routine antenatal anti-D prophylaxis (RAADP) in 2018. STUDY DESIGN AND METHODS: This was a nation-wide cohort study of 130 pregnancies affected by RhD alloimmunization in Iceland in the period from 1996 through 2015. Data were collected from transfusion medicine databases, medical records, and the Icelandic Medical Birth Register. RESULTS: Of 130 RhD alloimmunizations, 80 cases (61.5%) represented new RhD immunization in the current pregnancy. Sensitization was discovered in the third trimester in 41 (51.3%) and occurred in the first pregnancy in 14 cases (17.5%). The most likely causative immunization event was the index pregnancy for 45 (56.25%), a previous pregnancy/birth for 26 (32.5%), abortion for 3 (3.75%), and unknown for 6 women (7.5%). Higher anti-D titers were associated with shorter gestational length, cesarean sections, positive direct antiglobulin test (DAT), and severe HDFN. Intrauterine transfusion (IUT) was performed in five pregnancies (3.8%), and 35 of 132 (26.5%) live-born neonates received treatment for HDFN; 32 received phototherapy (24.2%), 13 exchange transfusion (9.8%), and seven simple blood transfusion (5.3%). CONCLUSION: In about half of cases, RhD alloimmunization was caused by the index pregnancy and discovered in the third trimester. Thus, the newly implemented RAADP protocol should be effective in reducing the incidence of RhD immunization in Iceland in the future.

Red cell alloimmunization: A 2020 update.

Management of maternal red cell alloimmunization has been revolutionized over the last 60 years. Advances in the prevention, screening, diagnosis, and treatment of alloimmune-induced fetal anemia make this condition an exemplar for contemporary practice in fetal therapy. Since survival is now an expectation, attention has turned to optimization of long-term outcomes following an alloimmunized pregnancy. In this review, the current management of red cell alloimmunization is described. Current research and future directions are discussed with particular emphasis on later life outcomes after alloimmune fetal anemia.

Targeted antenatal anti-D prophylaxis for RhD-negative pregnant women: a systematic review.

BACKGROUND: All non-sensitized Rhesus D (RhD)-negative pregnant women in Germany receive antenatal anti-D prophylaxis without knowledge of fetal RhD status. Non-invasive prenatal testing (NIPT) of cell-free fetal DNA in maternal plasma could avoid unnecessary anti-D administration. In this paper, we systematically reviewed the evidence on the benefit of NIPT for fetal RhD status in RhD-negative pregnant women. METHODS: We systematically searched several bibliographic databases, trial registries, and other sources (up to October 2019) for controlled intervention studies investigating NIPT for fetal RhD versus conventional anti-D prophylaxis. The focus was on the impact on fetal and maternal morbidity. We primarily considered direct evidence (from randomized controlled trials) or if unavailable, linked evidence (from diagnostic accuracy studies and from controlled intervention studies investigating the administration or withholding of anti-D prophylaxis). The results of diagnostic accuracy studies were pooled in bivariate meta-analyses. RESULTS: Neither direct evidence nor sufficient data for linked evidence were identified. Meta-analysis of data from about 60,000 participants showed high sensitivity (99.9%; 95% CI [99.5%; 100%] and specificity (99.2%; 95% CI [98.5%; 99.5%]). CONCLUSIONS: NIPT for fetal RhD status is equivalent to conventional serologic testing using the newborn's blood. Studies investigating patient-relevant outcomes are still lacking.

Implementation of high-throughput non-invasive prenatal testing for fetal RHD genotype testing in England: Results of a cross-sectional survey of maternity units and expert interviews.

BACKGROUND: Previously, routine antenatal anti-D prophylaxis (RAADP) was administered to all RhD-negative mothers to reduce the risk of sensitisation in the UK's National Health Service (NHS). If the baby is RhD-negative, RAADP is not required. In 2016, the UK National Institute for Health and Care Excellence (NICE) recommended non-invasive prenatal testing (NIPT) for fetal RHD genotype as a cost-effective option to guide RAADP. OBJECTIVES: To evaluate the implementation of high-throughput NIPT for fetal RHD genotype in maternity units in England by addressing research recommendations from the NICE. These were to reduce uncertainty around the resource use and cost of staff training, management of samples and results and record-keeping, as well as resultant changes to antenatal or post-partum care and performance of NIPT. METHODS: A cross-sectional survey was developed and sent to clinicians at 39 English NHS Trusts in May 2018. Qualitative interviews with seven individuals were conducted to explore missing or contraindicatory data. Qualitative findings were supplemented with NIPT test results (April 2017 to February 2019) from English hospitals. RESULTS: Staff reported that training took up to 30 minutes. There were no extra costs associated with sample management or additional appointments. Extra time required for record-keeping and management of test results was balanced later in the patient pathway. The antenatal pathway was not changed in the Trusts surveyed. The survey revealed that four post-partum scenarios were being used within English NHS Trusts. The frequency of inconclusive NIPT results was 4.3%. CONCLUSION: NIPT for fetal RHD genotype can be implemented without consuming substantial extra resources through incorporation into an existing patient pathway.

Very Prolonged Anti-D: Confusion Surrounding Alloimmunization After Extra Rh Immunoglobulin: A Case Report.

BACKGROUND: Rh immunoglobulin (RhIg) is usually detectable a maximum of 12 to 14 weeks after administration. Positive antibodies beyond this time frame suggests alloimmunization. CASE: A woman had three pregnancies over a 6-month period, with two first-trimester losses. She received RhIg in the first pregnancy but not in the second. Two months after the second loss, in her third pregnancy, she received RhIg at week 6 due to first-trimester bleeding. She was subsequently anti-D antibody positive up to week 28 with antibodies too low to titre, leading to confusion about whether alloimmunization had occurred. CONCLUSION: Rh Ig administration led to positive anti-D antibodies lasting 22 weeks, suggesting keeping this differential diagnosis in mind when suspecting alloimmunization with positive antibodies at levels too low to titre.

Targeted antenatal anti-D prophylaxis program for RhD-negative pregnant women - outcome of the first two years of a national program in Finland.

INTRODUCTION: The aim of this study was to assess the accuracy of the non-invasive fetal RHD test at 24-26 weeks of gestation as part of the national antenatal screening program to target routine antenatal anti-D prophylaxis (RAADP) at 28-30 weeks at women carrying an RhD-positive fetus. MATERIAL AND METHODS: A prospective cohort study involving all maternity care centers and delivery hospitals in Finland between February 2014 and January 2016. Fetal RHD genotyping using cell-free fetal DNA in maternal plasma was performed with real-time polymerase chain reaction in a centralized setting. The results were systematically compared with the serological newborn RhD typing. The main outcome measure was the accuracy of the fetal RHD assay; the secondary variable was compliance with the newly introduced RAADP program. RESULTS: Fetal RHD was screened from 10 814 women. For the detection of fetal RHD, sensitivity was 99.99% [95% confidence interval (CI) 99.92-99.99] and specificity 99.81% (95% CI 99.60-99.92). One false-negative and seven false-positive results were reported by the delivery hospitals in two years. The negative predictive value of the test was 99.97% (95% CI 99.81-99.99). At the end of the study period, over 98% of the RhD-negative women participated in the new screening program. CONCLUSIONS: The targeted RAAPD program was implemented effectively in the national maternity care program in Finland. An accurate fetal RHD screening test allows discontinuation of newborn testing without risking the postnatal prophylaxis program. In the future, the main area to investigate will be the clinical effect of RAADP on subsequent pregnancies.

Third trimester screening for alloimmunisation in Rhc-negative pregnant women: evaluation of the Dutch national screening programme.

OBJECTIVE: To evaluate the effect of red blood cell (RBC) antibody screening in the 27th week of pregnancy in Rhc-negative women, on detection of alloimmunisation, undetected at first trimester screening ('late' alloimmunisation), and subsequent haemolytic disease of the fetus and newborn (HDFN), to assess risk factors for late alloimmunisation. DESIGN: Prospective cohort and nested case-control study. SETTING: The Netherlands. POPULATION: Two-year nationwide cohort. METHODS: Prospective inclusion of Rhc-negative women with negative first trimester screening and of screen-negative controls. Assessment of incidence and numbers needed to screen (NNS) of late alloimmunisation and HDFN; logistic regression analysis to establish risk factors for late alloimmunisation. MAIN OUTCOME MEASURES: Late alloimmunisation, HDFN. RESULTS: Late alloimmunisation occurred in 99 of 62 096 (0.159%) Rhc-negative women; 90% had c/E antibodies and 10% non-Rhesus antibodies. Severe HDFN (fetal/neonatal transfusion) occurred in two of 62 096 (0.003%) of Rhc-negative women and 2% of late alloimmunisations; moderate HDFN (phototherapy) occurred in 20 children [22.5%; 95% confidence interval (CI), 13.8-31.1%]. Perinatal survival was 100%. The NNS to detect one HDFN case was 2823 (31 048 for severe, 3105 for moderate HDFN). Significant risk factors were former blood transfusion [odds ratio (OR), 10.4; 95% CI, 1.14-94.9], parity (P-1: OR, 11.8; 95% CI, 3.00-46.5; P > 1: OR, 7.77; 95% CI, 1.70-35.4) and amniocentesis/chorionic villus sampling during current pregnancy (OR, 9.20; 95% CI, 1.16-72.9). CONCLUSIONS: Additional screening of Rhc-negative women improved the detection of late alloimmunisation and HDFN, facilitating timely treatment, with a NNS of 2823. Independent risk factors for late alloimmunisation were blood transfusion, parity and chorionic villus sampling/amniocentesis in the current pregnancy. The occurrence of most factors before the current pregnancy suggests a secondary immune response explaining most late alloimmunisations. TWEETABLE ABSTRACT: Third trimester screening for alloimmunisation in Rhc-neg women improves detection and treatment of severe HDFN.

Prospective surveillance of D- recipients of D+ apheresis platelets: alloimmunization against D is not detected.

BACKGROUND: Recent retrospective studies indicate that D- recipients of D+ apheresis platelets (PLTs) are not alloimmunized to D. Our hospital policy is to offer RhIG to D- women of childbearing age who received D+ apheresis PLTs but not to other D- recipients of D+ apheresis PLTs. We instituted prospective surveillance of the D- recipients who were not given RhIG. STUDY DESIGN AND METHODS: All apheresis PLT recipients were prospectively entered into a database that recorded the patient's age, sex, diagnosis, D status, apheresis PLT transfusions, and antibody screen results from before and after PLT transfusions. Data are reported for PLTs transfused between October 16, 2012, and April 16, 2014, and antibody screens obtained through June 16, 2014. The analysis excludes neonates; women not more than 50 years of age; and patients who also received D+ red blood cells, received only D- PLTs, received RhIG, were previously alloimmunized to D, and did not have a follow-up antibody screen after the first D-incompatible apheresis PLT transfusion. RESULTS: A total of 158 of 1107 apheresis PLT recipients were D-. Seventy-nine were eligible for analysis based on the exclusion criteria listed above. None became alloimmunized to D during the observation interval. In 45 (57%) cases the last follow-up antibody screen was obtained at least 4 weeks after the first D-incompatible apheresis PLT transfusion. CONCLUSION: Prospective surveillance confirms prior retrospective observations that D- patients do not appear to risk D alloimmunization after receiving D+ apheresis PLTs.

Evaluation of different testing methods for identification of RhIG in red blood cell antibody detection.

BACKGROUND: RhIG has had great success in protecting fetuses from potential harm; however, little work has been done to demonstrate how long RhIG reactivity is detected in the mother after administration when using common red blood cell antibody detection methods. STUDY DESIGN AND METHODS: A retrospective investigation was performed examining positive antibody identification panels due to RhIG. These panels were run on solid-phase (SP) testing. The time to a positive result, length of detection, and positive strength of reactivity (PSR) were evaluated. Additionally, a comparative study was performed evaluating how sensitive SP, gel (GT), and tube testing (TT) were at detecting RhIG using serially diluted plasma samples spiked with different RhIG formulas. RESULTS: Retrospectively, most antibody identification panels by SP were positive 3.5 months after RhIG administration and demonstrated a strong PSR. The longest recorded positive panel was present at 4.5 months. RhIG administered intramuscularly could not be detected until several hours after injection. The comparative study showed that SP was the most sensitive method while GT and TT were comparable to one another in detecting RhIG. SP also recorded strong PSR at very low concentrations of RhIG. GT and TT recorded weak PSR even with higher concentrations of RhIG. CONCLUSION: SP is the most sensitive testing method and has the ability to detect RhIG 4 to 5 months after administration. TT and GT have the ability to detect RhIG up to 3 to 4 months after administration. Different RhIG formulas may show slightly different lengths of detection.

Non-invasive prenatal diagnosis of fetal RhD by using free fetal DNA.

OBJECTIVE: Anti-D immunoglobulin is applied to all pregnant women having RhD incompatibility to prevent hemolytic disease of the newborn. The aim of this study is to determine fetal RhD status in the Rh incompatible pregnancies with an non-invasive technique; free fetal DNA isolation from maternal circulation. In the case of Rh incompatibility especially with a history of previous fetal anemia, it can be beneficial to know Rh status antenatally in terms of monitoring fetuses with Rh positive [RhD(+)] status consciously. MATERIALS AND METHODS: Total free DNA was isolated in 50 Rh negative [RhD(-)] pregnant women, who had RhD alloimmunisation with their husbands. The gene in isolated DNA was investigated with TagMan prob and real time PCR by using primers belonging to exon 7 of the RhD gene. RESULTS: The authors analyzed 50 RhD(-) women by using quantitative real time PCR technique. Five of them were RhD(-) and the rest of them were found to be RhD(+). After birth one of the infants who were analyzed as RhD(+) were found to be RhD(-). CONCLUSION: The detection of fetal RhD status by using a non-invasive method from maternal circulation was found to be possible. Assessing fetal RhD status non-invasively by using free fetal DNA in maternal blood will be cost-efficient, avoiding unnecessary indirect Coombs test and unnecessary Rhogam applications that is used in RH incompatible pregnancies. This study will throw a fresh light on prenatal diagnosis.

[Erythrocyte alloimmunization in pregnant women, clinical importance and laboratory diagnostics]. / Erytrocytární aloimunizace tehotných zen, klinický význam a laboratorní diagnostika.

OBJECTIVE: The aim of this review is to give comprehensive summary of erythrocyte alloimunization of pregnant women, laboratory dignostics and clinical importance. DESIGN: Review. SETTING: University Hospital Olomouc, Transfusion Department, Department of Obstetrics and Gynecology. SUBJECT AND METHOD: Based on literature analysis using database search engines PubMed, Google Scholar, Ovid in field of erythrocyte antibodies, laboratory diagnostics and clinical importance up-to-date knowledge. CONCLUSION: Erythrocyte alloimunization anti-D antibodies decreases in connection with the introduction of immunoprofylaxis. Immunization of non RhD antibodies with impossibility using of immunoprofylaxis remains still clinical problem.

Performance in appropriate Rh testing and treatment with Rh immunoglobulin in the emergency department.

STUDY OBJECTIVE: The quality measure "Rh immunoglobulin administration for Rh-negative women at risk for fetal blood exposure" was recently endorsed by the National Quality Forum. No published data have shown a related performance gap in US emergency departments (EDs). We determine performance in a US ED for appropriate Rh testing and treatment among pregnant ED patients at risk of fetal blood exposure. METHODS: This was a retrospective, observational study in an urban, academic ED with 97,000 annual visits. We performed record review of all pregnant ED patients aged 14 to 50 years and presenting between June 1, 2009, and June 1, 2010, to determine whether a sensitizing event or a potential sensitizing event occurred and whether Rh testing and treatment with Rh immunoglobulin were performed when indicated. Performance rates were calculated under 2 different assumptions for patients without Rh testing ordered in the ED but who had previous data in the electronic medical record: (1) unless explicitly documented by the treating physician, previous Rh data were considered as not having been checked; and (2) when available in the electronic medical record, Rh status was always considered as having been checked. Interrater reliability was assessed for whether a trauma represented a sensitizing event. RESULTS: Among 1,465 patients identified, 808 met inclusion criteria; 560 had a sensitizing event and 248 had a potential sensitizing event. Interrater reliability for determination of sensitizing event or potential sensitizing event in trauma was moderate (κ=0.42). Performance rates for Rh testing among patients with sensitizing events, with potential sensitizing events, and overall were 73% (95% confidence interval [CI] 69% to 76%) (408/560), 36% (95% CI 31% to 43%) (90/248), and 62% (95% CI 58% to 65%) (498/808). Appropriate treatment for patients with a sensitizing event, with a potential sensitizing event, and overall was 56% (95% CI 39% to 71%) (19/34), 0% (95% CI 0% to 49%) (0/5), and 48% (95% CI 33% to 63%) (19/39). Assuming that physicians were aware of previous Rh results yielded performance rates of 96% (95% CI 93% to 97%) (535/560), 73% (95% CI 67% to 78%) (181/248), and 89% (95% CI 86% to 91%) (716/808) and treatment performance rates of 54% (95% CI 38% to 69%) (20/37), 0% (95% CI 0% to 30%) (0/11), and 42% (95% CI 29% to 56%) (20/48). CONCLUSION: In this single-center study, among patients with a sensitizing event, performance was moderate for Rh testing and treatment with Rh immunoglobulin. Despite lack of consensus or uncertainties in certain measure definitions, in at least 1 US academic ED there appears to be an opportunity for further evaluation and performance improvement in this area.

Prediction of the rate of decline in fetal hemoglobin levels between first and second transfusions in red cell alloimmune disease.

OBJECTIVE: To determine variables that predict the rate of decline in fetal hemoglobin levels in alloimmune disease. METHOD: Retrospective review of singleton pregnancies that underwent first and second intrauterine transfusions for treatment of fetal anemia because of maternal Rh alloimmunization in a tertiary referral center. RESULTS: Forty-one first intrauterine transfusions were performed at 26.1 weeks (standard deviation, SD, 4.6), mean volume of blood transfused was 44.4 mL (SD 23.5) and estimated feto-placental volume expansion was 51.3% (SD 14.5%). Between first and second transfusion, hemoglobin levels reduced on average 0.40 g/dl/day (SD 0.25). Stepwise multiple regression analysis demonstrated that this rate significantly correlated with hemoglobin levels after the first transfusion, the interval between both procedures, and middle cerebral artery systolic velocity before the second transfusion. CONCLUSION: The rate of decline in fetal hemoglobin levels between first and second transfusions in alloimmune disease can be predicted by a combination of hemoglobin levels after the first transfusion, interval between both procedures, and middle cerebral artery systolic velocity before the second transfusion.

Clinically silent massive fetomaternal hemorrhage: important lessons from an illustrative case.

Massive fetomaternal hemorrhage (FMH) >150 mL is rare and may occur in the absence of high-risk obstetrical events. The significance of FMH in Rh D-negative women is alloimmunization with an increased risk of hemolytic disease of the newborn in subsequent Rh D-positive pregnancies and adverse outcomes for the fetus/neonate. The Kleihauer-Betke (KB) acid elution test is used to quantify fetal erythrocytes in the circulation of Rh D-negative women postpartum and to calculate the dose of Rh immune globulin (RhIG) needed for prophylaxis against alloimmunization. In this case, the KB stain unexpectedly revealed 4.5% fetal cells, a finding consistent with a massive FMH of 225 mL, in the absence of a predisposing cause and clinical signs in the infant. This case underscores the importance of FMH quantification in all Rh D-negative women with Rh D-positive fetuses, uncomplicated pregnancies, and healthy newborns. We discuss factors that can affect KB test performance and caveats in interpretation.

The prevalence of Rhesus negativity among pregnant women in Enugu, Southeast Nigeria.

BACKGROUND: Hemolytic disease of the newborn, secondary to rhesus D (Rh D) iso-immunization, contributes significantly to perinatal morbidity and mortality. Prevalence data in Nigeria, and Southeast Nigeria in particular, is very scanty. This study was carried out to provide our experience in this preventable clinical condition in Enugu, Southeast Nigeria. OBJECTIVE: To determine the prevalence and trends of Rh D negativity among pregnant women in Enugu, Southeast Nigeria. MATERIALS AND METHODS: A 5-year retrospective study of rhesus negative women was carried out at the University of Nigeria Teaching Hospital, Enugu, Nigeria, between 1 st January 2000 and 31 st December 2004. RESULT: The prevalence rate of Rh D negative women in Enugu, Nigeria, is 4.5%. Out of 6306 women who booked for antenatal care, 282 (4.5%) were Rh D negative women. One hundred and eighty-two (182) (64.5%) of the Rh D negative women were of blood group O followed by blood group A 20%, blood group B 12.1%, and blood group AB 3.2%, respectively. CONCLUSION: There is a need for adequate counseling of pregnant women on the importance of Rh D negative factor during the antenatal period in order to prevent hemolytic disease of the newborn.

How we treat: transfusion medicine support of obstetric services.

BACKGROUND: Obstetric services depend on the transfusion service (TS) to provide diagnostic testing and blood component therapy for clinical care pathways. STUDY DESIGN AND METHODS: We describe three quality improvement (QI) initiatives implemented to improve TS support of obstetric services. RESULTS: We implemented a pathway for patients requiring an ABO/Rh order for every admission to obstetric services, along with reconciliation of the daily hospital birth manifest and TS umbilical cord log to identify every woman eligible for RhIG. After assessment over 6 months, 21 (1%) of 2041 women lacked an admission ABO/Rh; all subsequently had ABO/Rh determinations. Umbilical cords were missing for eight (0.4%) mothers; four were D- and received RhIG. We developed algorithms for diagnostic blood ordering for patients deemed at "low,""moderate," or "high" risk of blood transfusion. A 27% reduction in total diagnostic test volumes and 24% reduction in charges was documented after compared to before implementation. We analyzed the impact of our massive transfusion protocol (MTP) on blood inventory management for 31 (0.25%) women undergoing 12,945 deliveries, representing 11% of 286 MTPs for all clinical services over a 32-month interval. O- uncrossmatched red blood cells (RBCs) represented 103 (24%) of 421 RBC units issued. Wastage rates of RBCs, plasma, and platelets ordered and issued in the MTPs were 0.7, 16, and 3%, respectively. CONCLUSION: QI initiatives for RhIG prophylaxis, diagnostic blood test ordering, and MTP improve TS support of obstetric services.

Development of a transparent interactive decision interrogator to facilitate the decision-making process in health care.

BACKGROUND: Decisions about the use of new technologies in health care are often based on complex economic models. Decision makers frequently make informal judgments about evidence, uncertainty, and the assumptions that underpin these models. OBJECTIVES: Transparent interactive decision interrogator (TIDI) facilitates more formal critique of decision models by decision makers such as members of appraisal committees of the National Institute for Health and Clinical Excellence in the UK. By allowing them to run advanced statistical models under different scenarios in real time, TIDI can make the decision process more efficient and transparent, while avoiding limitations on pre-prepared analysis. METHODS: TIDI, programmed in Visual Basic for applications within Excel, provides an interface for controlling all components of a decision model developed in the appropriate software (e.g., meta-analysis in WinBUGS and the decision model in R) by linking software packages using RExcel and R2WinBUGS. TIDI's graphical controls allow the user to modify assumptions and to run the decision model, and results are returned to an Excel spreadsheet. A tool displaying tornado plots helps to evaluate the influence of individual parameters on the model outcomes, and an interactive meta-analysis module allows the user to select any combination of available studies, explore the impact of bias adjustment, and view results using forest plots. We demonstrate TIDI using an example of a decision model in antenatal care. CONCLUSION: Use of TIDI during the NICE appraisal of tumor necrosis factor-alpha inhibitors (in psoriatic arthritis) successfully demonstrated its ability to facilitate critiques of the decision models by decision makers.