Significance of immunohematologic testing in mother and newborn ABO incompatibility.

The aim of this study was to define risk factors for jaundice and anemia in newborns with a positive direct antiglobulin test (DAT) and/or with an incompatible crossmatch due to ABO incompatibility between mother and newborn. ABO incompatibility has become a more significant cause of hemolytic disease of the fetus and newborn since the introduction of effective anti-D prophylaxis. The condition is common and, if clinically significant at all, causes only mild jaundice, which can be treated with phototherapy (PT). However, rare and serious presentations, requiring transfusion therapy, have been noted. Clinical, laboratory, and immunohematologic data were collected retrospectively from medical records of ABO-incompatible newborns and their mothers over a 5-year period (2016-2020) from University Hospital Centre Zagreb. Two groups of newborns were compared: those who needed medical intervention because of hyperbilirubinemia or anemia and those who did not. Within the group of newborns requiring intervention, we also compared those with A and B blood groups. Over the 5-year period, 72 of 184 (39%) newborns required treatment. The treatment was PT in 71 (38%) newborns and erythrocyte transfusion in 2 (1%). In 112 (61%) newborns, ABO incompatibility was an accidental finding while performing blood group typing; these newborns did not require any therapy. In conclusion, we found a statistical, but not clinically significant, difference between the groups of treated and untreated newborns, related to the mode of delivery and DAT positivity within hours of delivery. There were no statistically significant differences in characteristics between the groups of treated newborns, except for two newborns with blood group A who received erythrocyte transfusions.

Is it acceptable to use coagulation plasma samples stored at room temperature and 4°C for 24 hours for additional prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin, and D-dimer testing?

INTRODUCTION: Coagulation laboratories are faced on daily basis with requests for additional testing in already analyzed fresh plasma samples. This prompted us to examine whether plasma samples stored at room temperature (RT), and 4°C for 24 hours can be accepted for additional prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen (Fbg), antithrombin (AT), and D-dimer testing. METHODS: We measured PT, aPTT, Fbg in 50 and AT in 30 plasma samples with normal and pathological values, within 4 hours of blood collection (baseline results) and after 24-hours storage at RT (primary tubes), and 4°C (aliquots). D-dimer stability was investigated in 20 samples stored in primary tubes at 4°C. RESULTS: No statistically significant difference between baseline results and results in samples stored at RT and 4°C was observed for PT (P=.938), aPTT (P=.186), Fbg (P=.962), AT (P=.713), and D-dimers (P=.169). The highest median percentage changes were found for aPTT, being more pronounced for samples stored at 4°C (13.0%) than at RT (8.7%). CONCLUSION: Plasma samples stored both at RT and 4°C for 24 hours are acceptable for additional PT, Fbg, and AT testing. Plasma samples stored 24 hours in primary tubes at 4°C are suitable for D-dimer testing.