All three of these examples in Table 4-6 could represent cases of missing anti-A or anti-B due to one of three causes:
| Examples | anti-A | anti-B | A1 cells | B cells | Tentative group | ||
|---|---|---|---|---|---|---|---|
| #1 | 4+ | -- | -- | -- | A | ||
| #2 | -- | 4+ | -- | -- | B (or AB*) | ||
| #3 | -- | -- | -- | -- | O |
| * | Also see Table 4-9 (weak or missing antigens) |
Patient is a newborn: Anti-A and anti-B are not present at birth and develop about 3-6 months of age. (Usually the reverse group is not done when grouping newborns.)
Patient is very elderly: Anti-A and anti-B levels decrease in old age because levels of immunoglobulins decrease. Because the levels may only be decreased and not totally missing, further investigation can be done. (Note: It would be unusual for an elderly person to totally lack ABO antibodies in the absence of an immune disorder.)
Patient has a- or hypogammaglobulinemia: Anti-A and anti-B will be weak or missing in patients with a gammaglobulinemia or hypogammaglobulinemia.
Read IS crossmatch, a Medline abstract about an early study to assess the safety of an immediate spin (IS) crossmatch at RT to detect ABO incompatibility. E-mail replies to Pat.
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| Weak or Missing Antibodies |