The Role of a Transfusion Laboratory in Antenatal Care in the UK Mr M.W. Brown FIBMS North Bristol NHS Trust

Overview of Antenatal Testing Overview of the use of Anti D ig. Overview of Laboratory Practice Experiences and findings in North Bristol

Objectives of the Testing Program Haemolytic Disease of the Newborn (HDN) –Prevention –Detection –Identify pregnancies at risk of HDN Group and Antibody Screen Mother Identify ABO & Rh D Type and Antibody status of mother in case of transfusion requirement

‘Booking’ Appointment (10/40) ABO and Rh D Type Antibody Screen –Positive Antibody Screen Identification –Clinically Significant Quantification (Anti - D, - c, - E, - e, - C, - K, - k, - Fya) (Anti - Cw, - Fyb, - Jka, - Jkb, Jk3, - S, - s, -M) Monitor at 4 weekly intervals Repeat at 28 weeks

28 weeks ABO and Rh D Type Antibody Screen –Positive Antibody Screen Identification –Anti – D, ? Prophylactic –Clinically Significant Quantification Monitor at weekly intervals Rh D Negative offer Rh D-ig. –Repeat at Delivery with a Cord Sample Rh D Negative, Rh D-ig.declined –Repeat at 34 weeks Rh D Positive & Antibody Screen Negative –No further samples

34 weeks ABO and Rh D Type Antibody Screen –Positive Antibody Screen Identification –Anti – D, ? Prophylactic –Clinically Significant Quantification Monitor at weekly intervals Rh D Negative and Ab. Screen Negative –Repeat at Delivery with a Cord Sample

At Delivery Mother (Rh D Neg and/or Ab. Screen Pos) –ABO and Rh D Type –Antibody Screen –Positive Antibody Screen Identification –Anti – D, ? Prophylactic Baby –ABO and Rh D Type –Direct Antiglobulin Test

Actions following Delivery Mother - Rh D Negative & Baby Rh D Positive Offer Rh D-ig. Baby – DAT Positive –? HDN –? Prophylactic Rh D-ig. –? ABO incompatibility

Use of Rh D-ig. Potential Sensitising Events –Amniocentesis, Cordocentesis –Other in-utero therapeutic intervention/surgery –Ante partum haemorrhage (APH) –Chorionic villus sampling –Ectopic pregnancy –External cephalic version –Fall / abdominal trauma –Intrauterine death –Miscarriage –Termination of pregnancy Pre 20 weeks i.u, Post 20 weeks - Min 500 i.u. with Foetal Leak Assessment

Use of Rh D-ig. Prophylactic during Pregnancy –2 doses 500 i.u. at 28 and 34 weeks or –1 dose 1500 i.u. at 28 weeks Prophylactic at Delivery –Minimum 500 i.u. –Additional if Foetal Leak > 4mls

Causes of Immunisation to Rh D Failure to recognise potential sensitising events Failure to assess the extent of Fetomaternal Haemorrhage (FMH) adequately Failure to comply with postpartum prophylaxis guidelines Refusal of Rh D-ig by the mother Incomplete adherence to guidelines (i.e. poor compliance with the second dose or timing). Late presentation to Maternity Services

Antenatal Anti D i.g. Audit (2007) 92% received their 1st dose of anti-D 87% received their 2nd dose Reasons for not receiving 1st dose: –Moved out of the area –Declined for reasons including: dislike injections concerned about blood products Husband Rh D Negative Reasons for not receiving 2nd dose: –Moved out of the area –Delivered at 31 – 33 weeks –Declined

Antenatal Anti D ig.Audit (2007) Timeframe between doses: 20% of women received their anti-D doses outside of the recommended 6 week interval Reasons for inaccurate timeframes: No stock in fridge when required Patient unavailable on required week Midwife unavailable on required week Patient failed to attend appointment Patient undecided at time of appointment

North Bristol Policy 1 dose 1500 i.u. at 28 weeks 1 dose 1500 i.u. at Delivery –Additional if FMH > 12 mls.

Method Selection Guidelines BCSH Guidelines 2004 –ABO (Monoclonal Anti-A, Anti-B, A 1 and B cells) –Rh D (2 x Monoclonal Anti-D not detecting D VI ) –Antibody Screening Indirect Antiglobulin Test R 1 w R 1 (R 1 R 1 ), R 2 R 2, rr Screening Cells Fya, Fyb, Jka, Jkb, S, s, - Homozygous K, k, M, N and Lea –Antibody Identification Antibody specificity assigned when reactive with at least two cells carrying the antigen and nonreactive with at least two red cells lacking the antigen.

Method Selection Guidelines BCSH Guidelines 2004 –Direct Antiglobulin Test (DAT) IgG specificity DAT testing on all cord samples of D positive infants born to D negative women. Not recommended. BCSH Guideline 2009 –Foetal Leak Assessment Acid Elution (Kleihauer) Screening & Quantification Flow Cytometry using IgG monoclonal anti-Rh D reagent fluorochrome

North Bristol NHS Trust (NBT) 2 acute sites (Southmead & Frenchay Hospital) 1,300 in-patient beds Trauma Centre and Maternity services Treated 490,000 patients and delivered 5,000 babies (2010) Bristol

Pathology Services  Blood Transfusion  Haematology  Immunology  Clinical Biochemistry  Cellular Pathology  Microbiology  Genetics  Point-of-care Services

Blood Transfusion Department Annual Workload (2010) NBT Total Group & Antibody Screen33,273 Antenatal Group & Screen13,621 Newborn Group 1,253 Foetal Leak Investigations 1,184 Antibody Investigation 1,439 Crossmatches (Serological) 2,827 Crossmatches (Electronic issue) 5,018 Transfused per annum (2010) Red cells13,161 Platelets 1,028 Fresh frozen plasma 1,418

Grifols DG Gel ® System

Results of Ante Natal Testing 26 months dataNo. Patients16958 Samples33199 Rh D Negative288417% Antibody Screen Positive3522% Prophylatic Anti D28010% Immune Anti D8 c7 E14 C+D1 K4 Fy(a)2 Cw7 Jka1 S2 M12 U1 Bga, Cob, Lea, Leb13

Change Control Process Documented Validation Plans for –All Manual and Automated Techniques –Automation Equipment –Interface connection to LIMS Staff Training and Competencies Amendment of SOP’s and Documentation

® Diamed® Classic Gel Station

Grifols DG Gel ® System

Validation Results In-house validation team Validation & Comparative data (1 week): 1,160 patient samples tested 1,041 Group & Antibody Screens 23 Crossmatches 45 Newborn Groups + DATs 51 Antibody Investigations

Comparative Data Discrepancies No. of events not detected DiamedGrifols ABO groups Reverse group not detected 11 Rhesus groupsNone-- Antibody screens Antibodies not detected 39 CrossmatchesNone- - Newborn Groups None--

Comparative Data (cont’d) Discrepancies No. of events not detected DiamedGrifols Antibody screens Proph. Anti-D 19 Anti-Jk(a) 1- Anti-c 1- Antibody Identification Anti-Jk(a) 1-

Weak Proph. Anti-D Investigation Method 200 Rh D Negative Antenatal patients tested with Enzyme-treated screening cells in addition to IAT screening. Antibodies detected by the Enzyme-treated cell technique were identified using 15-cell antibody identification panel. Samples found to contain Anti-D antibodies were sent for quantification at the Reference Laboratory, National Blood Service, Birmingham.

Weak Proph. Anti-D Investigation 200 RhD Negative Antenatal samples tested 26 Anti-D Abs by ENZ All Anti-D quantification < 0.1iu/mL 7 Non-specific ENZ Abs 33 IAT NEG, ENZ POS

Changing methodology and equipment requires Planning Resources Commitment Support

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