Systems and methods for testing and screening using compound bound substrates

A method of administering a red blood cell transfusion to a patient, wherein the red blood cell transfusion comprises red blood cells treated with a pathogen-inactivating compound β-alanine, N-(acridin-9-yl), 2-[bis(2-chloroethyl)amino]ethyl ester (S-303-treated RBCs), the method comprising:

• a) testing a sample from the patient for presence of antibodies reactive to the S-303-treated RBCs according to a method comprising:
• i) providing the sample from the patient, wherein the sample comprises serum or plasma;
• ii) contacting the sample with a first substrate, wherein a moiety is bound to the surface of the first substrate, and wherein the surface-bound moiety resulted from treating the first substrate with a compound of Formula VIII:
• where R1, R2, R3, R4, R5, R6, R7, and R8 are each —H;
• R20 is —H;
• and R21 is —R11—X-E, where —R11— is unsubstituted-C1-8alkyl-;
• X is independently —R11—;
• and E is N(R12)2;
• where —R12 is —CH2CH2-G, and where each G is independently —Cl, —Br, or —I, or a salt or stereoisomer thereof;
• iii) assaying an amount of binding between antibodies from the sample and the surface-bound moiety of the first substrate as compared to a reference, wherein the binding between the antibodies and the surface-bound moiety indicates the presence of antibodies in the sample that are reactive to the S-303-treated RBCs, wherein the reference is a second substrate that lacks the surface-bound moiety, and the second substrate is the same as the first substrate;
• b) determining whether the amount of binding is higher than the reference;
• and
• c) administering the red blood cell transfusion to the patient in accordance with the determination that the amount of binding is not higher than the reference.