Red blood cell antibody screening in pregnancy

'Old is gold' does conventional test tube method still reign supreme? An immuno-haematological survey of anti-D detection and titration in ante-natal cases among major hospitals across India

INTRODUCTION

Anti-D detection and titration plays a major role in RhD negative antenatal cases both, for monitoring maternal as well as fetal status as well as initiation of early therapeutic interventions, such as intra-uterine transfusions (IUT) to improve maternal as well as fetal morbidity and mortality and reduce the adverse effects of haemolytic disease of fetus and newborn (HDFN). We conducted a survey focusing on the policies and procedures of anti-D detection and titration among major tertiary care centres across India.

METHODOLOGY

The survey was drafted by a working group of transfusion medicine and immunohematology specialists from six different centres in India. Data were obtained via the use of an online questionnaire.

RESULTS

Results were categorised into four categories, Hospital information, immuno-haematological testing methodology, clinical significance of anti-D testing and the role of transfusion medicine specialists. The survey highlighted the modalities as well as the methodologies of anti-D detection and titration in antenatal women across different major tertiary care centres in India.

CONCLUSION

This survey provided a unique snapshot of the prevalent methodologies being employed by major tertiary care centres across the country for detection and titration of anti-D levels as well as the important role it plays in the therapy of affected antenatal women to minimise adverse effects on the fetus.

Red cell alloimmunization in pregnancy: a study from a premier tertiary care centre of Western India

OBJECTIVE

The study was conducted to determine the frequency of alloimmunization to various blood group antibodies in pregnant women, and the risk of hemolytic disease in the fetus and newborn.

METHODS

All antenatal women, irrespective of the period of gestation or obstetric history, were included, whereas those taking anti-D immune-prophylaxis or with a history of blood transfusion were excluded. Antibody screening and identification were performed using a Bio-Rad ID microtyping system.

RESULTS

Of 2,084 antenatal females, 1,765 were D-antigen positive and 319 D-antigen negative. Sixty-five (3.119%) women alloimmunized. Out of 54 (2.591%) who had sensitized to D-antigen, 11 (0.527%) also sensitized to other antibodies. These 11 alloantibodies identified included: anti-M (n=6; 9.23%), anti-C (n=1; 3.076%), anti-E (n=1; 1.538%), anti-e (n=1; 1.538%), anti-Lewis (a) (n=1; 1.538%), and unspecified antibodies (n=1; 1.538%). Multiple antibodies were seen in four patients that combined: anti-D and anti-C (n=2; 3.076%), anti-e and anti-c (n=1; 1.538%), and anti-D and anti-G (n=1; 1.538%).

CONCLUSION

The rate of alloimmunization in D-antigen-negative women was high. Apart from this, the alloimmunization rate in women with bad obstetric history was very high, at 8.1%. In developing countries such as India, universal antenatal antibody screening, though desirable, may not be justified at present, as the cost and infrastructure required would be immense because of the lower alloimmunization rates in RhD antigen-positive women. However, it is necessary to impose properly formulated protocols to screen pregnant women with bad obstetric history.

Lacunae in Laboratory Medicine Services and in Pathology Education in Medical Schools in India

CONTEXT.—

Laboratories of many medical college hospitals in India do not offer important diagnostic tests, most of which are routine in the West. This detracts from the service as well as the educational function of the college.

OBJECTIVES.—

To provide the background to pathology and laboratory medicine services and education in India, and to create a questionnaire that will put the lack of tertiary care laboratory services in perspective. This article will help illustrate the lacunae in laboratory medicine services and in the education of students. For this, we present information on the health services and pathology education facilities in India. We propose a questionnaire comprising 30 questions in various disciplines in pathology and laboratory medicine. These questions will help administrators and bureaucrats evaluate the status of the laboratories with respect to the services provided.

DATA SOURCES.—

Sources include Web sites of the government of India, including that of the National Accreditation Board for Testing and Calibration Laboratories; indexed medical journal articles; and standard books and white papers on health care in India. We also used our personal experiences and interpretations of the laboratory and medical education sector in India.

CONCLUSIONS.—

Medical colleges in India need to offer specialized diagnostic services if they are to achieve the targets of universal health care as well as turning out competent doctors. The agencies responsible for health care in India should use the questionnaire as a first step toward improving laboratory services. Other low- and middle-income countries should also adopt this method.

Reassessment of Critical Anti-D Antibody Titer in RhD Alloimmunized Antenatal Women

OBJECTIVE

In the setting of RhD-alloimmunized pregnancy, laboratory variations in critical titer (CT) of anti-D antibody may result in needless referrals or a compromised fetal outcome.

METHODS

RhD-alloimmunized pregnant women were included. Fetal outcome was categorized based on cord hemoglobin and interventions required. For 3 commonly used CTs of 8, 16, and 32, sensitivity and specificity as well as positive and negative predictive values were computed.

RESULTS

When compared with CTs of 16 and 32, we detected 6.9% and 19.4% more cases of moderate-severe hemolytic disease of the fetus and newborn by using 8 as the CT. However, this leads to greater rate of unnecessary referral (12.1%, 10/82) than a CT of 16 (8.2%, 6/73) and 32 (4.9%, 3/61). A CT of 8 demonstrated 100% sensitivity, but 12.1% (10/82) of patients were referred needlessly.

CONCLUSION

Because of its 100% sensitivity, we advocate decreasing the CT to 8. However, this may lead to unwarranted referrals.

Frequency of Red Cell Alloantibodies in Pregnant Females of Navsari District: An Experience that Favours Inclusion of Screening for Irregular Erythrocyte Antibody in Routine Antenatal Testing Profile

Background

Alloimmunisation due to irregular erythrocyte antibodies is a recognised cause of hemolytic disease of the fetus and newborn (HDFN). Prior knowledge of red cell alloimmunisation in pregnant females guides the obstetrician to monitor the foetus for HDFN and if required for appropriated intervention. As limited data are available on prevalence of red cell alloimmunisation in pregnant females in India, the current study was carried out to know the prevalence of red cell alloimmunisation in pregnant females coming at our laboratory.

Methods

Screening for irregular erythrocyte antibodies was performed in 1960 pregnant females after obtaining informed consent between June 2015 and June 2016. MatrixTM screening and identification reagent red cells from Tulip Diagnostics (P) Ltd were used, and column agglutination technique was employed as a method for the test.

Results

Twenty antibodies (all of single specificity) were detected in 1960 samples giving a prevalence rate of alloimmunisation of 1.02%. Out of the 20 antibodies, 18 were identified to be anti-D, 1 was anti-c and 1 antibody was anti-H. The results obtained were then compared with those reported in the literature.

Conclusion

Red cell alloimmunisation is not uncommonly observed in pregnant females; the information gained can help the obstetrician to identify high-risk cases to timely start antenatal and post-natal treatment. Obstetricians should request screening for irregular red cell antibody desirably in all pregnant females; however, if limiting factors are there, it should be done at least in select group of pregnant females having bad obstetric history.

Red cell alloimmunization in RhD positive pregnant women and neonatal outcome

The frequency of red blood cell (RBC) alloimmunization in RhD positive pregnant women is not known in our population. We planned to determine its frequency and correlation with neonatal outcome. We included 1000 RhD positive pregnant women: 500 had 'normal pregnancy' (Group I) and another 500 had 'high risk pregnancy' (Group II). ABO and extended Rh phenotyping were done by tube technique, antibody screening and identification by gel technique. For alloimmunized women, the paternal and neonatal ABO and extended Rh typing were done. Neonatal direct antiglobulin test (DAT) was also done and their clinical outcome observed. The frequency of RBC alloimmunization was 0.7% (7/1000) and all these women were from group II (p = 0.015). The alloantibodies were anti-E (85.7%), anti-c (71.4%), anti-Cw (14.3%) and anti-S (14.3%). Also, 6 women had history of transfusion (p < 0.01). Of the 7 neonates born to alloimmunized mothers, 4 (57.14%) had a positive DAT. The mean duration of phototherapy was higher in the DAT positive neonates (p < 0.01) and 2 (50%) required exchange transfusion. Thus, the frequency of alloimmunization was 0.7% in RhD positive pregnant women. High risk pregnancies and antenatal patients having a history of blood transfusion should be considered for regular antibody screening.

Red cell alloimmunization among antenatal women attending a tertiary care hospital in south India

BACKGROUND & OBJECTIVES

Detection of maternal alloimmunization against red cell antigens is vital in the management of haemolytic disease of the foetus and newborn (HDFN). This study was conducted to measure the presence of allosensitization to blood group antibodies in the antenatal women attending a tertiary care hospital and to observe the proportion of minor blood group antibodies to assess the benefit of screening for the same.

METHODS

All antenatal women registered in the hospital between January 2008 and January 2009, were screened for irregular antibodies using a commercial 3-cell antibody screening panel. Antibody identification was performed on samples found positive using a commercial 11 cell-panel.

RESULTS

Screening was performed on 5347 women, 339 (6.34%) of whom were Rh negative. Allosensitization was found in 79 women (1.48%; confidence interval 1.17 -1.84). In 29 of these 79 (37%) women the allo-antibodies could not be identified. In the remaining 50 women, 54 antibodies were characterized. A total of 40 clinically significant antibody specificities were identified among 36 women, of whom four were Rh(D) positive. Allosensitization with clinically significant antibodies was found in 9.43 per cent (confidence interval 6.55-13.06) Rh(D) negative and in 0.08 per cent (confidence interval .02-0.2) Rh(D) positive women. Anti D was the most frequent antibody found in 8.85 per cent Rh(D) negative women. The remaining clinically significant antibodies identified included anti-C, c, E, Jk(a), Jk(b), M and S. In Rh(D) negative women, anti-D and antibodies of the Rh system contributed 83.3 and 94.4 per cent of clinically significant antibodies. However, in Rh(D) positive women, non-Rh antibodies comprised three out of four clinically significant antibodies.

INTERPRETATION & CONCLUSIONS

The presence of alloimmunization in our study corroborated with data reported from India. The most frequent antibody was anti-D. However, a significant fraction was non-D. Alloimmunization among Rh(D) positive women though low as compared to Rh(D) negative women, included clinically significant antibodies, and most of these were non Rh.