# RBCX Calculation Tool vs ASPN Go

The clearest difference is update cadence: ASPN Go at every 6 months against RBCX Calculation Tool's every 15 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

RBCX Calculation Tool ships an update every 15 months, ASPN Go every 6 months. The most recent releases landed on October 11, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | RBCX Calculation Tool | ASPN Go |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (5 ratings)](https://appshunter.io/ios/app/rbcx-calculation-tool/id1457982121/reviews)** | — |
| Number of ratings | **5** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 15 months | **Every 6 months** |
| Monetization | Free | — |
| Size | 26 MB | 55 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Terumo BCT](https://appshunter.io/developer/1023483386) | [The American Society of Pediatric Nephrology](https://appshunter.io/developer/1733265245) |

## What reviewers say

### RBCX Calculation Tool

[App page](https://appshunter.io/ios/app/rbcx-calculation-tool/id1457982121)

This medical tool assists healthcare professionals in estimating the required replacement fluid volume for red blood cell exchange procedures on the Spectra Optia system. It calculates volumes based on patient and fluid data to achieve target Hct and FCR, and can suggest custom primes.

**Highlights:** Estimate replacement fluid volume, Calculate target Hct and FCR, Determine custom prime recommendation, Uses patient and fluid data, Supports Spectra Optia system

**Features:** macOS Compatibility

**In-app purchases:** none


### ASPN Go

[App page](https://appshunter.io/ios/app/aspn-go/id6478542675)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is RBCX Calculation Tool free?

RBCX Calculation Tool is free to download, with no in-app purchases.

### Is ASPN Go free?

ASPN Go is free to download, with no in-app purchases.

### Do RBCX Calculation Tool or ASPN Go have ads?

Neither RBCX Calculation Tool nor ASPN Go shows ads.

### Which is updated more often, RBCX Calculation Tool or ASPN Go?

RBCX Calculation Tool ships an update every 15 months, and ASPN Go every 6 months. Most recently, RBCX Calculation Tool was updated on October 11, 2026 and ASPN Go on October 9, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*