4 mL Sample Cup Caps, Perforated Top, LDPE — Direct-Probe Auto-Analyzer Closure (300-1999-020)
These natural Low-Density Polyethylene (LDPE) perforated top sample cup caps are designed for high-throughput clinical laboratory workflows where analyzer probes must aspirate directly through the cap without a decapping step. Part number 300-1999-020 fits Caplugs® Evergreen 4 mL round-bottom and flat-bottom sample cups and is supplied non-sterile in convenient 1000/Bag quantities. The perforated top delivers both direct probe-pierce access and controlled evaporation management during refrigerated pre-analytical staging — two performance advantages in a single closure.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (MPN) | 300-1999-020 |
| Cap Type | Perforated Top |
| Material | Low-Density Polyethylene (LDPE) |
| Color | Natural |
| Cup Compatibility | Caplugs® Evergreen 4 mL round-bottom and flat-bottom sample cups |
| Probe Access | Yes — perforated top allows direct probe aspiration without cap removal |
| Sealing | Partial closure — perforations provide controlled evaporation management |
| Sterility | Non-Sterile |
| Pack Size | 1000/Bag |
| BPA / Phthalates | BPA-free; no phthalate plasticizers |
| Country of Origin | USA (California) |
Applications
- Direct probe aspiration on auto-analyzers — probe pierces through the perforated cap, eliminating the decapping step and reducing aerosol exposure risk in high-volume clinical chemistry workflows
- Pre-analytical refrigerated staging — perforations allow controlled evaporation, reducing sample concentration drift during hold times compared to fully open cups
- Frozen storage at –20 °C — LDPE flexibility maintains snap-on retention across the full clinical temperature range from room temperature through refrigerated and frozen conditions
- Urine, serum, and plasma specimen management in clinical labs, hospitals, and reference laboratories running high-throughput chemistry panels
Compatibility
These caps are engineered to fit Caplugs® Evergreen 4 mL sample cups used in probe-based auto-analyzer loading workflows, including those running on Roche Cobas and Beckman AU/DxC chemistry analyzer series, where the aspiration probe pierces directly through the perforated top. By eliminating the uncapping step entirely, labs running Roche or Beckman platforms can improve throughput and minimize technician handling. Confirm cup-to-cap fit against your specific sample cup model before transitioning from OEM or alternative closures, as cap retention geometry varies by cup manufacturer.
Chemical Resistance
| Reagent / Condition | Compatibility |
|---|---|
| Urine, serum, plasma (aqueous specimens) | Excellent |
| Aqueous buffers and saline | Excellent |
| Dilute acids and bases | Good |
| Standard assay diluents | Excellent |
| Alcohols (short-term contact) | Good |
| Chlorinated or aromatic solvents | Not recommended |
| Autoclave sterilization | Not recommended |
Quality & Procurement
Made in USA (California), these Caplugs® Evergreen caps are manufactured from BPA-free, phthalate-free LDPE resin selected for the flexible snap-on retention that high-volume clinical workflows demand — rigid materials crack under repeated capping cycles, while LDPE maintains consistent snap engagement across thousands of applications without fracture or retention loss. LabSupplies.com is an authorized Caplugs® Evergreen dealer shipping from USA inventory, with tiered volume pricing available for clinical labs, hospital systems, and reference laboratory procurement programs.
Frequently Asked Questions
Can analyzer probes aspirate directly through these caps without removing them?
Yes — the perforated top is specifically designed for direct probe-pierce aspiration, eliminating the decapping step in auto-analyzer workflows and reducing both cycle time and aerosol exposure for laboratory staff.
Do the perforations cause significant sample evaporation during storage?
The perforations provide controlled evaporation — meaningfully less concentration change than a fully open cup — making these caps suitable for refrigerated pre-analytical staging. For workflows requiring a fully sealed closure, flat top cap alternatives are available separately.
Are these caps compatible with all Caplugs® Evergreen 4 mL sample cups?
They are designed to fit both round-bottom and flat-bottom Caplugs® Evergreen 4 mL sample cups. If you are using sample cups from a different manufacturer, verify cap-to-cup retention geometry before committing to a large purchase.
Are these caps sterile, and can they be autoclaved?
These caps are supplied non-sterile and are not recommended for autoclave sterilization. LDPE softens at autoclave temperatures, which can compromise cap geometry and snap-on retention.