Panel Reactive Antibody Calculator

Calculator Inputs

Total panel cells tested

Reactive cells

Weak positive cells

Class I cells tested

Class I reactive cells

Class II cells tested

Class II reactive cells

Current unacceptable antigen count

Historic unacceptable antigen count

Manual review adjustment %

Moderate band starts at %

High band starts at %

Very high band starts at %

Weighted antigen rows

Use one row per antigen: antigen, population frequency %, yes/no.

Notes

Formula Used

The standard panel reactive antibody value is calculated as: PRA % = reactive panel cells ÷ total panel cells × 100.

Class values use the same method for Class I and Class II subsets. The weighted estimate uses: Weighted estimate = [1 - Π(1 - antigen frequency)] × 100. Only antigens marked yes are included.

The combined review score averages the standard PRA and weighted estimate when both are available. The manual adjustment is then added. The final value is capped between 0% and 100%.

How to Use This Calculator

Enter the total tested panel cells.
Enter the number of reactive panel cells.
Add Class I and Class II counts when available.
List antigen rows with frequency and yes or no status.
Use the adjustment field only for documented review assumptions.
Press Calculate to show results below the header.
Use CSV or PDF download for saved records.

Example Data Table

Case	Total Panel	Reactive Cells	Standard PRA	Unacceptable Frequencies	Weighted Estimate	Review Note
Example A	100	25	25.00%	18%, 8%, 14%	34.18%	Moderate review pattern
Example B	96	80	83.33%	22%, 16%, 11%, 9%	47.13%	High count pattern
Example C	120	6	5.00%	7%	7.00%	Lower review pattern

Panel Reactive Antibody Guide

Panel reactive antibody testing helps describe how broadly a recipient’s serum reacts with a donor panel. A higher value can suggest a wider set of unacceptable donor targets. A lower value can suggest fewer reactions. This calculator turns panel counts into a standard percentage. It also lets you enter class I, class II, and antigen frequency information.

Basic Meaning

The basic panel method is simple. Divide reactive panel cells by total panel cells. Then multiply by one hundred. The result is the PRA percentage. This works best when the panel represents the donor population used by the laboratory. It does not replace a laboratory report.

Weighted Antigen Review

Weighted antigen review adds another view. Enter one antigen per line. Add its population frequency. Mark whether it is unacceptable. The tool multiplies the chance of avoiding each selected antigen. It then estimates the chance that at least one unacceptable antigen appears. This resembles a calculated PRA concept. It remains an estimate, because real allocation systems use detailed haplotype and population models.

Class Pattern Notes

Class results help separate antibody patterns. Class I reactions usually relate to HLA-A, HLA-B, or HLA-C targets. Class II reactions often relate to HLA-DR, HLA-DQ, or HLA-DP targets. Seeing both values can support clearer notes for a transplant team. It can also help compare current and historic sensitization.

Best Practice

Use the result as a planning aid. Check every input before saving. Confirm the total panel count. Do not enter a reactive count larger than the tested count. Use the notes field for assay method, sample date, and special assumptions. Export the results when you need a simple record.

Review Reminder

Important clinical choices should rely on approved laboratory systems. A transplant professional should review antibody specificity, mean fluorescence intensity, dilution effects, crossmatch history, and donor typing. This page only organizes values. It is useful for education, auditing, and quick scenario comparison. It should not decide donor acceptance by itself.

Consistent Tracking

For best results, keep same method when comparing dates. Mixing kits can change apparent reactions. Review weak positives carefully. Some centers track them separately. Others include them after confirmation. The calculator therefore stores weak counts, current unacceptable antigens, and historic unacceptable antigens. These fields support notes. They do not change the formal panel percentage unless you add an adjustment.

FAQs

1. What does PRA mean?

PRA means panel reactive antibody. It estimates how much a recipient sample reacts against a donor panel. Higher values may mean broader sensitization.

2. What is the basic PRA formula?

The formula is reactive panel cells divided by total panel cells, then multiplied by 100. The result is shown as a percentage.

3. What is weighted antigen estimate?

It estimates the chance of meeting at least one selected unacceptable antigen, using entered population frequencies. It is only a simplified estimate.

4. Can this replace a laboratory report?

No. This tool is for education, documentation, and quick review. Laboratory systems and transplant specialists should guide clinical decisions.

5. Why include Class I and Class II counts?

Class values help separate antibody patterns. They can show whether reactions mainly involve Class I, Class II, or both groups.

6. What should I enter in antigen rows?

Enter one antigen per line. Use this format: antigen name, population frequency, yes or no. Mark yes for unacceptable antigens.

7. What does manual adjustment do?

It adds a documented review change to the combined score. Use it only when you have a clear reason or review note.

8. Why export CSV or PDF?

Exports help save calculations, compare scenarios, and share a simple record. Always verify entries before using the exported file.