Cord Blood Grouping and Cross-Matching Process
I must clarify that the question appears to be asking about ABO/Rh blood typing and antibody screening of cord blood samples, which is a fundamentally different process from the HLA typing used for cord blood transplantation that dominates the provided evidence. The evidence focuses almost entirely on HLA matching for transplantation purposes, not routine blood group typing.
Standard Blood Group Typing of Cord Blood
For routine ABO/Rh blood grouping of newborns, cord blood is collected from the umbilical vein immediately after delivery and tested using standard serologic methods to determine ABO type and Rh status. 1
Collection Process
- Blood is collected from the umbilical cord vein immediately after vaginal delivery or cesarean section 2
- The sample can remain viable for testing at 4°C or room temperature (25°C) for at least 3 days, but not at 37°C 2
- Mean collection volumes typically range around 79 ± 26 ml 2
Standard Testing for Blood Banking
- ABO typing is performed using standard forward and reverse typing methods 2
- Rh (D) antigen status is determined
- Direct antiglobulin test (DAT/Coombs) may be performed if maternal antibodies are suspected
- Approximately 5.0 ml of cord blood is required for routine laboratory testing 2
HLA Typing for Transplantation (Different Context)
If the question pertains to cord blood banking for transplantation, the process is entirely different:
HLA Typing Requirements
Cord blood units must be typed by DNA-based methods for HLA-A and -B at minimum antigen-level resolution and for DRB1 at high resolution, with HLA-C typing strongly recommended. 3
- High-resolution typing for all loci helps characterize potential allele-level mismatches 3
- For transplantation, ≥4/6 loci should be matched for malignant hematological diseases 4
Cross-Matching for Transplantation
The American Society of Transplantation recommends using flow cytometry or complement-dependent cytotoxicity assay for all patients 4
- A positive crossmatch against T cell or B cell donor targets is a contraindication to transplantation 4
- This differs fundamentally from routine blood bank cross-matching
Additional Testing for Banking
- Sterility control (bacterial contamination reduced to <1% with proper technique) 2
- Viral screening including HBsAg, anti-HCV, anti-HIV, CMV by PCR (only 0.3% positive) 2
- Assessment of progenitor cells by colony-forming assays and CD34+ status 2
- Total nucleated cell count requirements: >2.5-4.0 × 10^7/kg 4
Critical Distinction
The provided evidence does not address routine blood bank cross-matching procedures for cord blood. Standard cross-matching for transfusion compatibility involves mixing recipient serum with donor red cells to detect incompatibility 5, but this specific methodology for cord blood samples is not detailed in the evidence provided.