Discipline - Blood typing
ABO blood groups and Rhesus (Rh) factor typing
Slide agglutination test
First added in 2018
Changed in 2020
Changed in 2022
Determination of Physiological Status
To determine ABO groups and Rh factor
Capillary whole blood, Venous whole blood
Summary of evidence evaluation
POC dry cards are a simple-to-use, cheap and easy-to-implement test. They aim to diagnose a severe condition which can have a significant impact on the lives of a large group of unborn children and their parents. Treatment for this condition appears to be effective. The test requires limited infrastructure, facilities and training. The stability of samples is described in detail in technical documents (from the EldonCard producer). Documentation provided on diagnostic accuracy (e.g. sensitivity, specificity) in a real-world setting by untrained personnel is limited and of low quality. Nonetheless, given the clear effect (100% sensitivity and specificity) and the link with indirect evidence on concordance with laboratory tests (in a research setting), there is little reason to doubt the accuracy of this test. This is underpinned by the recommendation of several international guidelines. Although the impact on clinical outcomes was not demonstrated using empirical studies (as is the case with the majority of diagnostic tests), the alternative of not providing this test would have severe consequences for a large group of unborn children and their parents. Given the anticipated costs of US$ 1, minimal investment in supporting infrastructure and training, and the severity of the condition if left undetected and untreated, POC cards are expected to have a net positive cost–effectiveness. The availability of treatment, however, is a prerequisite for the IVD test to have any meaningful clinical impact. If availability is ensured, adopting the POC dry format card on the list would be recommended.
Summary of SAGE IVD deliberations
The ABO blood groups and Rh typing test is a straightforward, easy-to-use POC test for determining ABO groups and Rh. The test is very important in the context of maternal health care, in particular when laboratory-based tests are unavailable. Several SAGE IVD members would have preferred a little more data on the impact of the test on clinical outcomes. The group noted that in the case of strong D antigen expression, concordance is reported to be 99.9%; performance in the case of weak D antigen expression is somewhat lower. One SAGE IVD member reported 100% concordance based on literature he consulted, although minor variants in ABO were not detected. The experts proposed changing the title as submitted – A, B and O blood groups and Rhesus (Rh) factor POC dry format card – to “ABO blood groups and Rhesus factor typing point-of-care test” to be consistent with the way the test is reported in the literature. SAGE IVD made special note of the problem of weak D detection because it will have an impact on implementation. Literature cited in the discussion: Ravichandran S, Abraham P, Sugendran K, Hedegaard HO, Jones E. Trial and evaluation of dry format Eldon card for ABO & Rh blood grouping – “a new card concept”. Natl J Basic Med Sci. 2016;6(4):168–71.
SAGE IVD recommendation
SAGE IVD recommended including the ABO blood groups and Rh factor typing test category in EDL 4 *as a general IVD for use in community settings and health facilities without laboratories (EDL 4, Section I.a); *using a POC test format; *using capillary whole blood as specimen type; *to determine ABO groups and Rh factor. The group also noted that detection of the weak D antigen appears to be a limitation.
Details of submission from 2022
Disease condition and impact on patients: The proposed test intends to reduce the burden of Rh haemolytic disease of the fetus and newborn and complications of the disease, and expand access to blood products in settings with limited access to laboratory services. Rh isoimmunization of fetus or newborn (also referred as Rh haemolytic disease or erythroblastosis fetalis) is caused by the passage of anti-Rh (anti-D) antibodies from an Rh-negative mother to her Rh-positive fetus, and results in stillbirths, neonatal deaths and brain damage due to severe hyperbilirubinaemia. At birth infants may have anaemia, hydrops fetalis, jaundice and hepatosplenomegaly. Anti-Rh antibody development is caused by the entry of fetal Rh positive red blood cells into the maternal circulation. It occurs in about 15% of pregnancies in which the fetus is Rh positive and the mother is Rh negative (1). Anti-Rh antibodies usually develop in the mother after birth, meaning that her first baby is typically not affected by Rh disease. However, in subsequent pregnancies, if the fetus is Rh-positive, the baby could be affected. A series reported in the 1970s, when adequate prevention and management were not available, indicates that without treatment these pregnancies result in stillbirths (13%), neonatal deaths (25%) or severe hyperbilirubinaemia (25%), which can develop into irreversible brain damage (kernicterus) in 25% of cases but requires treatment in 33% of cases (2). Even after therapy, which includes exchange transfusion, many surviving infants are at risk of permanent hearing loss. Usually identified on antenatal screening tests, Rh disease is now uncommon in high-income countries (3). Administration of Rh immunoglobulin to the Rh-negative mother postpartum and during pregnancy is very effective in disease prevention (4). When studying the gap between annual doses of anti-Rh(D) given and the annual doses required, it has been concluded that the highest priority is met only in high-income countries and countries such as Brazil, Czechia, Croatia, Greece, Hungary, the Islamic Republic of Iran, Lithuania, Malaysia, Saudi Arabia, Sri Lanka, the Republic of Korea, Thailand, Türkiye and Uruguay (4). Treatment of a baby with Rh disease includes exchange blood transfusions, phototherapy and fetal transfusion. Prevention is preferable to avoid severe morbidity and mortality, as well as the cost and complications of therapy (3). ABO haemolytic disease occurs when the mother’s blood type is O and the infant’s blood type is A or B. Maternal anti-A or anti-B immunoglobulins can cross the placenta and cause haemolysis in the infant. ABO is more frequent than Rh haemolytic disease; however, when promptly identified, ABO haemolytic disease is less likely to require exchange transfusion, or to cause brain damage or death than is Rh disease. Haemolysis with anaemia may progress during the first few weeks of life, and therefore careful monitoring of the newborn is necessary. There are no studies on the global burden of this condition. Bilirubin-induced brain injury (kernicterus) is caused by severe jaundice and may result in death or long-term neurodevelopmental impairment. Jaundice within the first 24 hours of life is more likely to be haemolytic; total bilirubin levels may rise rapidly to very high levels. The main causes are Rh disease, ABO incompatibility, minor antigen incompatibility, glucose-6-phosphate dehydrogenase (G6PD) deficiency, hereditary spherocytosis and congenital infections. Extremely severe jaundice (bilirubin > 25 mg/dL) is estimated to affect 481 000 late-preterm and term newborns annually; 114 000 die and more than 63 000 survive with moderate or severe long-term neurological impairment (5). Currently, standard practice in most countries during prenatal and antenatal care includes screening for ABO and Rh blood types in the mother. This test therefore identifies women with a blood group that is Rh-negative to administer postpartum anti-Rh immunoglobulin to avoid severe disease in future pregnancies. In the case of G6PD deficiency, neonatal screening using a blood spot has been shown to be effective and is cost-effective in regions with prevalence greater than 5%. Pre-discharge examination of women and their newborns will help identify early jaundice requiring more investigations, including blood typing and Coombs testing, and treatment. Does the test meet a medical need?: The POC dry format card provides a reliable blood typing result that supports a final diagnosis of Rh incompatibility in pregnant women. The test is innovative and has the potential to address a need that is not met by current technologies. Existing strategies require venous blood samples, shipping the sample to specialized laboratory services and relocating Rh-negative women to deliver treatment. Compared with slide blood typing tests, the dry format card requires no electricity, no cold chain, no laboratory and no daily control of reagents, and therefore can be used as a POC test (6, 7). The dry format card is currently being used in clinical practice in high-income countries and low- and middle-income countries (LMICs). In the United Kingdom the test is used to rule out Rh-negative women during pregnancy; and in LMICs the test has been used by Doctors Without Borders/Médecins Sans Frontières in emergency situations. Preliminary studies on feasibility and acceptability in LMICs show that the POC dry format card is accurate, user-friendly and acceptable for use by health professionals, lay workers and tested users (7, 8, 9). While there are no studies on the cost–effectiveness of the POC test, prevention of Rh disease has been included among high-impact interventions to reduce stillbirths and neonatal deaths (10). How the test is used: This POC test represents the first step in prevention of Rh disease by identifying Rh-negative women who can then receive preventive treatment with anti-D immunoglobulins (11). Additionally, the test will aid in the diagnosis of ABO incompatibility as the cause for haemolysis in newborns. Once a newborn is diagnosed, appropriate management of jaundice, anaemia and other complications can be initiated to prevent long-term disability and death.
Public health relevance
Prevalence: In LMICs access to laboratory facilities, prophylaxis and treatment for this condition is limited. Therefore, Rh disease continues to be a public health problem affecting more than 150 000 children annually (12). The prevalence of Rh negativity is not known in many LMICs. In Nigeria and India, it has been estimated at around 5% and in China at about 1%, whereas in Europe and North America prevalence is around 15% (3). Recent studies in Pakistan and Nigeria have found a prevalence comparable with that of industrialized countries (8, 9). However, due to the size of LMIC populations, millions of pregnant women are at risk. High fertility rates in some countries may also play a role as Rh disease becomes more severe with subsequent pregnancies. It is estimated that 50% of women around the world who require this type of immunoprophylaxis do not receive it (4). Globally, untreated Rh disease causes 52 000 stillbirths, 98 000 neonatal deaths, 67 000 cases of hyperbilirubinaemia and 17 000 cases of kernicterus each year (12). Socioeconomic impact: Not provided.
WHO or other clinical guidelines relevant to the test
Guidelines for preventing Rh disease published by the International Federation of Gynecology and Obstetrics/International Confederation of Midwives (FIGO/ICM) in 2021 (11) provide recommendations to address the global burden of Rh disease, to be implemented according to a country’s health system capacity (see box 1 on page 146 of the FIGO/ICM guideline). Measures to prevent sensitization to Rh(D): High priority *Determine the maternal Rh factor, preferably in early pregnancy. *For Rh(D)-negative women, determine the Rh factor of the newborn from umbilical cord blood. *Administer anti-Rh(D) immunoglobulin within 72 hours of delivery to women with an Rh(D)-positive newborn, unless already sensitized. *Use a dose of 500 IU (100 μg) of anti-Rh(D) immunoglobulin; if affordable and with sufficient supply, 1500 IU (300 μg) may be given, as is common in high-income countries. The intramuscular route is as effective as the intravenous route. Middle priority *Routine anti-Rh(D) prophylaxis during pregnancy: 1500 IU (300 μg) at 28–34 weeks. *Anti-Rh(D) immunoglobulin prophylaxis (500 IU; 100 μg) after a surgical abortion or ectopic pregnancy (all gestational ages), or after spontaneous or medical abortion/miscarriage after 10 weeks. *Anti-Rh(D) prophylaxis after bleeding, abdominal trauma in pregnancy and/or fetal death (500 or 1500 IU; 100 or 300 μg) during the second or third trimester. The Kleihauer-Betke test can be used to estimate the optimal dose. Low priority *Anti-Rh(D) prophylaxis after amniocentesis, chorionic villus sampling or external cephalic version (500 IU; 100 μg). The FIGO/ICM guidelines specify that a prerequisite for prevention of Rh(D) sensitization is a priori knowledge of maternal Rh status and that the Rh(D) factor can be determined by collecting venous or capillary blood samples at local health care facilities and using classical or POC serologic methods. The guidelines also state that Rh(D) type should preferably be determined in the first trimester, because indications for anti-Rh(D) immunoprophylaxis may arise early in pregnancy, for example after miscarriage or ectopic pregnancy. As reported in the FIGO/ICM guidelines, evidence shows that postpartum administration of anti-Rh(D) immunoglobulin reduces this risk to approximately 1.5% and is the most effective intervention in preventing Rh disease in subsequent pregnancies. Therefore, this approach should have the highest priority in countries and/or regions where no, or inadequate, prophylaxis is currently provided. Prenatal administration seems to reduce sensitization further, from approximately 1.5% (achieved by administration of postpartum anti-Rh(D) immunoglobulin) to approximately 0.5%.
Evidence for clinical usefulness and impact
No systematic reviews of the test’s clinical accuracy yet exist. However, four studies have been published on the clinical accuracy, stability and reliability of the dry format POC test under different conditions in high- and middle-income countries. The multicentre performance study published by Eldon Biologicals in 2004 evaluated the diagnostic accuracy of the dry format card test by comparing results obtained blindly using EldonCards with results from conventional blood typing techniques in four blood testing centres in Denmark, Germany, Italy and the United Kingdom (13). Of 2990 non-special samples regarding ABO blood types, 2988 concordant results were found at the initial testing (> 99.9% concordance). Of the eight weak A samples, three were detected by the dry card test, four were doubtfully positive and one was not detected. Of the 2988 samples, 2373 were found to be strong Rhesus D’s by conventional testing. Of these, 2372 were detected by the experimental EldonCard at initial testing (> 99.9% concordance). Of the 39 weak Rh(D) samples, seven were detected by the anti-D formulation already in use on commercial EldonCards. The two new, experimental anti-D formulations on the cards were able to detect 15 and 19 of the weak D samples. The study concluded that the results of the ABO typing as well as the Rh(D) typing (including the results of the typing of weak D samples) show that an EldonCard is a reliable blood typing device which can be used for blood typing of patients and for primary screening of blood donors. Bienek et al. assessed the accuracy of two dry card blood typing kits (the Eldon Home Kit 2511 and the ABO-Rh Combination Blood Typing Experiment Kit), tested under simulated military field conditions (6) and after long-term storage at various temperatures and humidities (14). Rates of positive tests among control groups, experimental groups and industry standards were measured and analysed using the chi-square and Fisher’s exact tests to identify significant differences (P ≤ 0.05). When the Eldon Home Kit 2511 was used under various operational conditions, the results were comparable to those obtained with the control group and with the industry standard. However, performance of the ABO-Rh Combination Blood Typing Experiment Kit was adversely affected by prolonged storage at temperatures above 37°C, indicating that performance of available kits varies with products and environmental conditions (6). Ravichandran et al. evaluated the accuracy and reliability of the EldonCard test compared with the standard conventional slide and tube method in 808 volunteers selected randomly from Vinayaka Missions University, Salem, India. Compared with the standard laboratory method, both the sensitivity and specificity of the EldonCard method, as well as the positive and negative predictive value (PPV and NPV), were found to be 100%. The percentage of false positives and false negatives was 0% (7). Primary studies on the POC dry format card test for blood group typing utility and impact have been conducted in Nigeria and Pakistan. Preliminary results have been presented at scientific meetings, and peer-reviewed papers are expected by the end of this year. A study in Pakistan of the willingness of pregnant women to receive the POC test and the ability of health professionals to administer it and interpret the results showed 100% acceptance of the test and of treatment among Rh‑positive women. Interpretation of the results had 100% concordance between health professionals and supervisors. These findings indicate that it will be feasible to implement a community-based programme for Rh haemolytic disease elimination in rural Pakistan (8). Studies in Nigeria assessed feasibility and acceptability of the POC test in community settings targeting pregnant women and schoolchildren. The POC test was easy to perform and acceptable. In addition, it was easier for women to report their blood group through the card provided with the test result (9). Implementation studies in Ghana, Kenya, Kyrgyzstan, Madagascar and Mexico are underway to develop community-based programmes to identify women who are Rh negative and to provide them with prophylaxis.
Evidence for economic impact and/or cost–effectiveness
Ethical issues, equity and human rights issues
The likelihood of an Rh-negative woman to have her baby affected by Rh disease is determined by where she lives. In high-income countries, stillbirth, neonatal mortality and disability due to this condition are uncommon. In contrast, in LMICs newborns affected by Rh disease often die either through lack of care at the lower level or inability to afford tertiary-level care. Inequities exist between and within countries, with women from the poorest communities facing the greatest barriers to access. In LMICs a large proportion of women do not have access to laboratory or preventive services. The use of this ABO blood grouping and Rh factor typing POC dry format card will expand coverage of essential interventions for maternal and newborn health and reduce inequity. Women without access to laboratory facilities would know their Rh(D) antigen status and blood group and receive advice on accessing preventive care for Rh disease. Midwives could screen pregnant women in primary care facilities and at the home and immediately provide prophylactic treatment with anti-D immunoglobulin. Diagnosis of haemolytic disease of the newborn will proceed more rapidly, and treatment could start to reduce the risk of kernicterus. Access to the screening test for Rh-negative and/or ABO status combined with access to the recommended treatment for preventing disease in pregnant women and for managing affected fetuses and newborns will lead to rapid elimination of the burden of Rh and ABO disease in less-developed countries (3, 4). In addition, the POC dry format card could contribute to reducing maternal deaths due to obstetric haemorrhage by increasing access to blood products in hard-to-reach settings through better access to blood typing for the pregnant women and in the general population. No ethical issues were identified.
1. Ascari WQ, Levine P, Pollack W. Incidence of maternal Rh immunization by ABO compatible and incompatible pregnancies. BMJ. 1969;1:399–401. 2. Walker WC. Haemolytic disease of the newborn. In: Gairdner D, Hull D, editors. Recent advances in paediatrics, 4th edition. London: JA Churchill; 1971. 3. Zipursky A, Bhutani VK, Odame I. Rhesus disease: a global prevention strategy. Lancet Child Adolesc Health. 2018;2(7):536–42. doi:10.1016/ S2352-4642(18)30071-3. 4. Pegoraro V, Urbinati D, Visser GHA, Di Renzo GC, Zipursky A, Stotler BA et al. Hemolytic disease of the foetus and newborn due to Rh(D) incompatibility: a preventable disease that still produces significant morbidity and mortality in children. PLoS One. 2020;15(7):e0235807. doi:10.1371/journal.pone.0235807. 5. Bhutani VK, Zipursky A, Blencowe H, Khanna R, Sgro M, Ebbesen F et al. Neonatal hyperbilirubinemia and Rhesus disease of the newborn: incidence and impairment estimates for 2010 at regional and global levels. Pediatr Res. 2013 Dec;74 (Suppl 1):86–100. doi:10.1038/pr.2013.208. 6. Bienek DR, Charlton DG. Accuracy of user-friendly blood typing kits tested under simulated military field conditions. Mil Med. 2011;176(4):454. 7. Ravichandran S, Abraham P, Sugendran K, Hedegaard HO, Jones E. Trial and evaluation of dry format Eldon card for ABO & Rh blood grouping – “a new card concept”. Natl J Basic Med Sci. 2016;6(4):168–71. 8. Pell L. Models of implementation of Rh prophylaxis in rural settings: project update and panel discussion. In: Open Symposium on Global Eradication of Rh Disease: Victories and Pitfalls, Florence, Italy, 28 September 2019. (Preliminary results of a feasibility study in Pakistan; peer-reviewed publication in progress) 9. Okolo AA. Current issues on Rh disease: perspective from Nigeria. The 36th Conference of the International Society for Blood Transfusion, virtual meeting, 12–16 December 2020. (Feasibility and acceptability of POC test in community settings targeting pregnant women and school children in Nigeria; peer-reviewed publication in progress) 10. Bhutta ZA, Das JK, Bahl R, Lawn JE, Salam RA, Paul VK et al. Can available interventions end preventable deaths in mothers, newborn babies, and stillbirths, and at what cost? Lancet. 2014 Jul 26;384(9940):347–70. doi:10.1016/S0140-6736(14)60792-3. 11. Visser GH, Thommesen T, Di Renzo GC, Nassar AH, Spitalnik SL. FIGO/ICM guidelines for preventing Rhesus disease: a call to action. Int J Gynecol Obstet. 2021;152(2):144–47 (http://doi.org/10.1002/ijgo.13459, accessed 30 July 2023). 12. Zipursky A, Bhutani VK. Impact of Rhesus disease on the global problem of bilirubin-induced neurologic dysfunction. Semin Fetal Neonatal Med. 2015;20(1):2–5. 13. Testing blood types using Eldon Cards prepared with monoclonal antibodies anti-A, anti-B, and anti-D. Multi centre performance study on 3000 blood samples. Gentofte: Eldon Biologicals; 2004. 14. Bienek DR, Chang CK, Charlton DG. Stability of user-friendly blood typing kits stored under typical military field conditions. Mil Med. 2009;174(10):1075.