Technical FAQs
Contact: technical.service@quotientbd.com
Currently we perform “weak D testing” on all the patient samples we test, which of your Anti-Ds should we consider using?
The ALBAclone® Anti-D blend is our most comparable alternative to the reagents you are currently using. The Anti-D blend is an all-round product that can be read at immediate spin, then incubated and taken through the indirect antiglobulin test (IAT) to detect weak D.
Currently we perform immediate spin testing only, and do not perform D testing at the IAT phase, on potential transfusion recipients, obstetric patients, and unit rechecks. Which Anti-D should we consider using?
Either the ALBAclone® Anti-D alpha or ALBAclone® Anti-D beta will serve as an appropriate alternative to the reagent you are currently using. These Anti-Ds will detect most weak Ds, but not the DVI variant on immediate spin, and are not designed to be tested at the IAT phase. They also have the added benefit of being from different cell lines, but are both directed at the same D epitope. If you are performing D typing in duplicate, prior to an immediate spin crossmatch, both could be used. When used in concert for initial, and repeat/confirmation testing, they give the advantage of two sources of anti-D, but limit the likelihood of discrepant results.
Currently we perform “weak D testing” on newborns and/ or donors for product labeling, which of your Anti-Ds should we consider using?
Either the ALBAclone® Anti-D delta or the ALBAclone® Anti-D blend will serve as an appropriate alternative to the reagents you are currently using. The Anti-D delta provides the extra advantage of providing the same results as would be obtained using a standard blend product, without requiring Indirect Antiglobulin Testing, saving time and additional expense.
Do you offer an Anti-D that can be used to perform weak D testing on patients with Positive DAT?
The ALBAclone® Anti-D delta is a FDA licensed product which can be used to test for weak D and partial D on immediate spin or 15 minute incubation, but does not require Indirect Antiglobulin Testing. As long as the Rh control is negative the D typing result can be considered valid using the Anti-D delta.
Is it possible to have Quotient Anti-D reagents from different cell lines, one that is appropriate for most transfusion patients and one capable of weak D testing for say cord blood?
Yes, there are two ALBAclone® product combinations that would meet your need. The Anti-D alpha is appropriate for most transfusion patients, while our Anti-D blend is from a different cell line but can detect weak-D through IAT. Additionally, our Anti-D beta also would be appropriate for transfusion patients, while the Anti-D delta is from a different cell line and can detect weak D at immediate spin.
Aren’t we required to perform weak D and partial D testing by an Indirect Antiglobulin Test method to meet regulatory requirements?
Not exactly. The requirement is to perform testing that will detect weak and partial Ds. While most reagents available are only able to detect weak or partial D using the Indirect Antiglobulin Test method, the method is not required. The ALBAclone® Anti-D delta is a FDA licensed product that can be used to test for weak D and partial D, and thus does not require the IAT step, saving time and additional expense.
Do you have suggestions or cautions for a new user with your products?
In order to assure clear demonstration of weak D and partial D antigens, our Anti-D reagents have potentiators that may exhibit a false positive reaction if the reagents or relevant samples are tested at 18°C or below. These reactions are easy to identify, as they generally weaken at 37°C.
Our Anti-N and Anti-M reagents are very quick, requiring a short 5 minute incubation, at 20 – 25C. It is important that the reagents are at room temperature prior to testing. If these reagents are removed from the refrigerator and used immediately, it is likely that the incubation temperature will not be correct, and weak false positives may be seen.
The Anti-M reagent reacts optimally at pH 8.5 and is extremely sensitive to pH to allow for the testing to be completed with only 5 minutes of incubation. Buffered saline will affect pH levels, so be sure to utilize red cells suspended in unbuffered/ unstabilized normal saline.
Some manufacturers do not include Anti-A,B in their reagent Anti-A,B and instead mix Anti-A and Anti-B together, does Quotient’s product contain actual Anti-A,B?
Yes, Anti-A,B is included in the Quotient reagent so it will detect most weak subgroups of A, especially Ax. The reagent is an excellent choice for rechecking units and provides the information you need when attempting to resolve ABO discrepancies that are the result of weak subgroups of A.
What is all the hype about cell lines? As long as the reagent works, why should I care about cell lines?
Cell lines indicate the “pedigree” of the cells producing the antibody used in a monoclonal reagent. Each cell line actually has its own specificity and you will occasionally see differences between the reactions from different cell lines for the same antibody specificity. AABB Standards requires that IRLs have two examples of some antisera. The laboratory staff needs to determine the cell lines used in the reagents they purchase to make sure they have two examples because it is not unusual for multiple manufacturers to utilize the same cell line. Quotient primarily utilizes cell lines that have not been previously distributed in the United States and can aid IRLs in meeting this requirement.