ASTM D5712-15 (2025) PDF

Full title and description

Standard Test Method for Analysis of Aqueous Extractable Protein in Latex, Natural Rubber, and Elastomeric Products Using the Modified Lowry Method (ASTM D5712-15). This test method specifies extraction, precipitation and colorimetric determination (modified Lowry) of total aqueous extractable protein from natural rubber/latex and elastomeric products for quality control and biocompatibility assessment.

Abstract

ASTM D5712-15 describes a laboratory procedure to extract water‑soluble proteins from latex, natural rubber (NR) and elastomeric products, concentrate and remove interfering substances by precipitation, then quantify proteins colorimetrically using the modified Lowry assay with a protein standard. The method is intended as a reference procedure for measuring residual extractable protein levels used in manufacturing control, specification, and comparison with other analytical methods.

General information

• Status: Active (current test method; reapproval cycle documented).
• Publication date: Original designation 2015 (D5712-15); reapproved/maintained in later reapproval cycles (noted 2020 and reissued listings with a 2025 reapproval record).
• Publisher: ASTM International.
• ICS / categories: 83.040.10 (Latex and raw rubber).
• Edition / version: D5712‑15 (reference method); shown as D5712‑15 with reapproval notation in subsequent years (example listings: D5712‑15(2020), D5712‑15(2025)).
• Number of pages: 9 pages (standard document length).

Scope

This test method covers determination of the amount of total aqueous extractable protein associated with natural rubber, latex and elastomeric products. Water‑soluble proteins are extracted into a buffered solution, precipitated to concentrate and remove interfering substances, redissolved and quantified colorimetrically by the modified Lowry method. The method reports results in micrograms per dm2 (or comparable area/mass units) and is intended for use in laboratories with appropriately trained analysts. The method is not validated for all lubricated products (for example certain condom lubricants may interfere) and alternative validated methods may be used for routine QC if correlated to this reference method.

Key topics and requirements

• Extraction of water‑soluble proteins from product specimens using a defined buffer system and controlled conditions.
• Protein precipitation step to concentrate extract and reduce assay interferences.
• Quantitation by the modified Lowry colorimetric assay using a calibrated protein standard; reporting of detection and quantitation limits and units (µg per dm² or equivalent).
• Procedural controls, blank corrections and steps to minimize matrix interferences.
• Notes on scope limits (products with certain lubricants not validated) and allowance for alternative validated methods when correlated to this reference method.

Typical use and users

Used by materials and QC laboratories in medical device and glove manufacturers, suppliers of latex/elastomeric components, third‑party testing labs and regulatory/compliance groups concerned with residual protein levels and potential allergenicity. Typical users include laboratory analysts, QA/QC managers, product development scientists and compliance officers evaluating latex products for healthcare, consumer goods and industrial applications.

Related standards

Commonly referenced and complementary standards include immunoassay‑based methods for latex protein (for example ASTM D6499 and other ELISA procedures), extraction protocols for chemical allergens (related D‑series methods), and product specifications for gloves and medical devices that reference extractable protein limits. Users should consult the ASTM D11 committee listings and related test methods for correlation and validation guidance.

Keywords

extractable protein, modified Lowry, natural rubber, latex, elastomeric products, aqueous extraction, protein assay, ASTM D5712, residual protein, glove testing.

FAQ

Q: What is this standard?

A: ASTM D5712‑15 is a test method that defines a laboratory procedure (modified Lowry) to extract and quantify aqueous extractable proteins from latex, natural rubber and elastomeric products. It serves as a reference method for measuring residual protein levels.

Q: What does it cover?

A: It covers specimen extraction, protein precipitation and concentration, and colorimetric protein determination using the modified Lowry assay, including requirements to control interferences and report results in µg per unit area or mass. It also notes product classes (e.g., lubricated products) for which the method has limited validation.

Q: Who typically uses it?

A: Manufacturing QC laboratories for gloves and elastomeric medical products, independent testing laboratories, material scientists, and regulatory/compliance personnel assessing latex protein content and potential allergenicity risk.

Q: Is it current or superseded?

A: The D5712 procedure (designation D5712‑15) is published and maintained by ASTM International and has been listed with reapproval/maintenance records in subsequent years (examples include reapproval notation in 2020 and listings showing reissued/reapproved status in 2025). Consult ASTM or an authorized distributor for the absolute latest revision or withdrawal notices before relying on a specific edition.

Q: Is it part of a series?

A: It is part of the ASTM D11 committee’s body of standards for rubber and elastomer testing and is often used alongside other latex/rubber test methods (such as immunoassay and extraction standards) when evaluating product safety and performance.

Q: What are the key keywords?

A: Extractable protein, modified Lowry, latex, natural rubber, elastomeric products, protein assay, residual protein, ASTM D5712.