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10 Tips Fluid Handling & IVD Technology Cheat Sheet (DRAFT) by [deleted]

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Introd­uction

At the nexus of these demands for testing produc­tivity and instrument reliab­ility lie the fluid handling systems that facilitate diverse testing, buffering, washing, and waste removal. Connectors are a critical component in a fluid handling systems, and using the ideal connectors and other system components can increase ease of use, minimize operator error, and increase testing safety — all important factors in the drive toward higher produc­tivity and reliab­ility.

Following are 10 tips for applying advanced connector features and techno­logies to help device manufa­cturers design world-­class fluid handling systems for diagnostic instru­ments.

1. Ensure Material and Media Compat­ibility

Material compat­ibility between connectors or other fluid handling components and the fluids used in the test setting is often overlo­oked, and a mismatch can be the root cause of costly mainte­nance due to leaks, contam­ina­tion, or corrosion. In IVD applic­ations, consider any cleaning solutions or other chemicals (e.g., bleach, hydrogen peroxide, or isopropyl alcohol) that may be flushed through the fluid lines or wiped on the exterior. Some high-end applic­ations involving stronger acids or solvents may require components to be made of engineered polymers such as PEEK or PVDF to maintain compat­ibi­lity.

2. Specify Non-Sp­ill/Dry Break Valved Connec­tions

Connectors with integral valves create a cleaner and safer connec­tion, elimin­ating the need for clamps or secondary shutoff valves and enhancing the overall perception of the instru­ment. Valved connectors prevent spills upon discon­nection and also prevent the entry of air into the system. There are many styles of valves with varying flow rates and pressure drops

3. Track Reagent Batches at the Point of Use

Connectors with radio frequency identi­fic­ation (RFID) capabi­lities help facilitate safe and efficient fluid connec­tions while avoiding harmful and expensive mistakes, reducing liability and improving process manage­ment. Intell­igent RFID-e­nabled coupling applic­ations include real-time reagent inventory monito­ring, batch identi­fic­ation, brand and product protec­tion, and expiration date tracking.

These types of couplings are currently being used with clinical diagnostic lab equipment. Thanks to the RFID-e­nabled connec­tion, labs can track the amounts of reagents used on each piece of equipment to confirm approp­riate inventory levels and ensure the availa­bility of sufficient reagent to complete the testing cycle. In addition, the couplings confirm that the right reagent is being used with the diagnostic equipment, which eliminates errors and mitigates equipment downtime due to the use of “off brand” consumable products.

4. Connect Multiple Fluid Lines at Once

Consol­idating multiple fluid lines into a single connection can greatly improve servic­eab­ility and prevent miscon­nec­tions. Lines can include dissimilar fluids or gases and use either pressure or vacuum to drive fluid through an instru­ment. Multi-line connec­tions on waste containers are partic­ularly valuable in providing the necessary supply, empty, and vacuum lines all in a single interface. New technology even allows electrical lines to be integrated into a hybrid connection point where fluids and data can be hooked up in a single quick operation.
 

5. Use Disposable Packaging

Although reagents are typically provided in disposable packaging with easy access ports, it often makes sense to implement a similar packaging strategy on bulk fluid or waste containers as well. Using bag-in-box style packaging to store bulk reagents and wash or buffer solutions eliminates inacce­ssible fluid below a dip-tube and allows for nearly 100% fluid utiliz­ation. It can also mean elimin­ating expensive, reusable caps or port fittings in exchange for cost-e­ffe­ctive puncture seal connectors that streamline interc­hanges.

6. Implement Gravity Fed Plumbing w/Shutoff Valves

Why specify expensive and complex pumps onto the instrument when gravity can feed on-board fluidics? Using couplings with shutoff valves eliminates the risk of spilling fluids during inverted instal­lation and ensures 100% evacuation of fluids from the bottle or reservoir. In this setup, non-spill valves also minimize air inclusion (the volume of air introduced into the system each time the coupler is connec­ted). Venting to the bottle can easily be accomp­lished with a similar dip-tube as right-side up bottle systems.

7. Color Code/P­hys­ically Key Multiple Fluid Lines

Another critical variable that plays into human factors engine­ering is the potential for miscon­necting dissimilar fluid lines. This can be a costly mistake that leads to extensive washing and flushing of supply lines if a biohaz­ardous waste line is inadve­rtently connected to a reagent line heading to test vessels. Using color-­coded or physically keyed connectors to prevent connection errors is especially critical on fluid lines in large automated immuno­assay instru­ments where multiple reagent supply lines are co-located with rinse and waste lines.

8. Don’t Let Partic­ulates Clog Your System

Along with the obvious concern over invali­dating a test due to foreign partic­ulate, fluid systems also rely on clean flow paths. Pumps, filters, valves, and microbore tubing are at risk of becoming clogged by partic­ulate that can originate from fluid system compon­ents. It is important to review the quality standards of fluid-­han­dling component suppliers and to ensure that machining burrs or other foreign partic­ulates will not contam­inate fluid lines and wreak havoc on instrument components downst­ream.

9. Cost Effective Level Sensing for Bulk Fluids

Detecting fluid levels in bulk solutions and waste containers is essential to avoid instrument downtime and extra operator mainte­nance time. Float switches provide cost-e­ffe­ctive, single­-point detection when a bottle is full/empty or can be used in a modular design to detect multiple critical points in a bottle. Altern­ati­vely, many systems use load cells or conductive probes that provide continuous level detection and more precise measur­ements. For applic­ations that require level sensing capabi­lities but involve partic­ularly caustic media or are sensitive to microbial contam­ina­tion, products like capaci­tance and optical sensors can provide non-co­ntact level sensing. These products can be partic­ularly valuable when handling fluids with a tendency to produce salt build up or bottles that are extra vulnerable to damage from a user.

10. Seek Help from Supplier Experts

Have a fluid handling question? Ask the experts at fluid handling component companies for advice on common issues, improving fluidics designs, or custom­izing standard products for unique applic­ations. Suppliers usually employ design engineers and applic­ation specia­lists who can answer questions and help design seamless fluid handling solutions for specific instrument needs.