100–300 µL Sample Cups, Screw Caps, HDPE, Natural — 300-3008-020 | 1500/Bag | Caplugs® Evergreen

False Bottom Tube Screw Caps, HDPE, Natural — 300-3008-020 | 1500/Bag

Technical Narrative

The Caplugs® Evergreen is a High-Density Polyethylene (HDPE) false bottom tube screw cap — a precision-engineered tube closure with an internal false bottom insert that raises the effective well floor of standard test tubes, reducing the minimum sample volume required for automated analyzer aspiration. Auto-analyzers have a fixed dead volume — the minimum volume that must be present in the sample tube for the probe to aspirate without drawing air. In standard tubes without a false bottom, this dead volume is wasted specimen that cannot be analyzed. The false bottom raises the well floor to meet the probe at a smaller total volume — enabling complete analysis from micro-volume specimens that would otherwise be insufficient for the analyzer's minimum sample requirement.

This is the critical application for pediatric and neonatal clinical chemistry: fingerstick blood draws and heel-stick collections from neonates yield volumes as low as 100–300 µL — far less than the dead volume of standard clinical chemistry tubes. A false bottom cap concentrates this micro-volume at the well bottom, allowing the analyzer probe to aspirate the complete sample without dead-volume loss. The screw-cap closure provides a secure, leak-free seal during centrifugation (for serum separation) and refrigerated storage before analysis. HDPE construction provides autoclave compatibility for pre-sterilized supply, broad chemical resistance to clinical specimen matrices, and the rigidity required for consistent screw-cap engagement over repeated use cycles.

At $124.48 per 1500/Bag — $0.0830 per cap — the delivers false-bottom micro-volume conservation at per-cap economics for high-volume pediatric and neonatal specimen processing programs.

Technical Specifications — Caplugs® Evergreen

False Bottom Cap Application Compatibility —

The false bottom screw cap reduces dead volume in standard test tubes for the following micro-volume applications:

False bottom insert height is fixed — confirm compatibility with your specific tube format and analyzer probe depth specification before bulk purchase. Request a sample to validate probe-to-insert clearance with your analyzer before volume commitment.

Chemical Resistance — High-Density Polyethylene (HDPE)

HDPE provides broad chemical resistance and autoclave compatibility — superior to LDPE for screw-cap closure applications.

Laboratory Applications

The serves neonatal and pediatric clinical chemistry laboratories processing micro-volume heel-stick and fingerstick specimens; reference laboratory programs conserving precious biobank specimens; point-of-care programs processing capillary micro-samples; clinical chemistry programs reducing minimum sample volume requirements for automated analyzers; oncology programs conserving rare biopsy specimen volumes for multiple test panels; and any laboratory application where maximizing analysis from minimum sample volume is a clinical or research requirement.

U.S. Manufacturing, Quality & Institutional Procurement

Every Caplugs® Evergreen lot is precision-molded at our California manufacturing facility and subject to rigorous dimensional inspection and material purity verification. We supply reference laboratories, hospital systems, and federal procurement offices under institutional pricing programs with blanket-order support and same-day shipping. Request a free sample below to validate fit before committing to volume.

Frequently Asked Questions — Caplugs® Evergreen

What is a false bottom tube cap and how does it reduce dead volume?

A false bottom tube cap has an internal insert that protrudes into the tube when the cap is screwed on, raising the effective tube floor to a higher position than the actual tube bottom. Auto-analyzers have a fixed aspiration dead volume — the minimum volume that must be in the tube for the probe to aspirate without drawing air. Without a false bottom, this dead volume sits at the bottom of a standard tube and is wasted. With a false bottom cap, the same specimen volume sits higher in the tube, above the false floor, at the probe's accessible aspiration height — allowing the analyzer to access the complete micro-volume specimen without dead-volume loss.

Is the false bottom cap compatible with centrifugation for serum separation?

Yes. The screw cap provides a secure, leak-free closure during centrifugation for serum separation. The HDPE screw-thread engagement maintains cap retention through standard centrifuge speeds used for serum separation (1,000–2,000 × g for 10 minutes). The false bottom insert concentrates the specimen volume at the accessible position after centrifugation. Confirm centrifuge compatibility with your rotor and tube format before use.

Are the false bottom caps autoclave-compatible for pre-sterilized supply?

Yes. HDPE is autoclave-compatible at 121°C / 15 psi — unlike LDPE stopper caps which are not autoclave-compatible. This makes the suitable for pre-sterilized supply in neonatal intensive care and pediatric clinical chemistry programs where sterile cap supply is required before micro-volume specimen loading. Autoclave caps in a sealed pouch and allow to cool before use.