rbc_compatibility_screen: RBC Units to Screen for Compatibility

In cliot: Clinical Indices and Outcomes Tools

RBC Units to Screen for Compatibility

Description

Calculates the estimated number of red blood cell (RBC) units that need to be screened to find a specified number of antigen-negative units for a patient with red cell alloantibodies. The calculation uses standard antigen-negative prevalence rates (based on a predominantly Caucasian population data from the AABB).

Usage

rbc_compatibility_screen(units_needed, antigens_selected)

Arguments

units_needed	Numeric. The number of compatible units required for transfusion.
antigens_selected	Character vector. A list of antigens for which the donor units must be negative. Supported codes: "d" (RhD), "c_big" (C), "c_little" (c), "e_big" (E), "e_little" (e), "k_big" (K/Kell), "k_little" (k/Cellano), "fya" (Duffy a), "fyb" (Duffy b), "jka" (Kidd a), "jkb" (Kidd b), "lea" (Lewis a), "leb" (Lewis b), "m", "n", "s_big" (S), "s_little" (s), "p1".

Details

The formula is:

Units\_to\_Screen = \frac{Units\_Needed}{P_1 \times P_2 \times ... \times P_n}

Where P is the prevalence of antigen-negative donors in the population for each selected antibody.

Value

A list containing:

Units_to_Screen	The estimated number of units to crossmatch (rounded up).
Combined_Antigen_Negative_Frequency	The mathematical probability of finding a unit negative for all selected antigens.

References

Fung MK, et al. AABB Technical Manual. 18th ed. Bethesda, MD: AABB; 2014.

Examples

# Example 1: Anti-K and Anti-E
# K negative freq ~91%, E negative freq ~71%
# Need 2 units: 2 / (0.91 * 0.71) = 3.1 -> 4 units
rbc_compatibility_screen(2, c("k_big", "e_big"))

# Example 2: Multiple Antibodies (Anti-c, Anti-Fya)
# c negative ~20%, Fya negative ~34%
# Need 2 units: 2 / (0.20 * 0.34) = 29.4 -> 30 units
rbc_compatibility_screen(2, c("c_little", "fya"))

cliot documentation built on Dec. 1, 2025, 1:06 a.m.