# K251875: LifeScale Gram Negative Kit (LSGN) with the LifeScale AST system

- Pathway: 510(k) (Traditional)
- Applicant: Affinity Biosensors, LLC
- Decided: Oct 27, 2025 after 131 days
- Product code: SAN (Automated Antimicrobial Susceptibility Test System For Positive Blood Culture Samples)
- Device class: 2
- Regulation: 21 CFR 866.1650
- Recalls of this device: none
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 4 generations back to DEN160032 (2017). 4 ancestors in all.
No later device cites it as a predicate yet.
0 of 5 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- K211815: LifeScale Gram Negative Kit (LSGN) with the LifeScale AST System, Affinity Biosensors (2024) Summary page 6.
- K241324: LifeScale Gram Negative Kit (LSGN) with the LifeScale AST system, Affinity Biosensors, LLC (2024) Summary page 6.

## Indications for use
The LifeScale AST system is a multiplexed in vitro diagnostic test that uses a microfluidic sensor and resonant frequency to calculate organism concentration and/or mass distribution for quantitative antimicrobial susceptibility testing (AST). Testing is performed directly on blood cultures signaled as positive by a continuous monitoring blood culture system and confirmed by Gram stain. The LifeScale AST system does not provide organism identification and is not indicated for use with polymicrobial samples. Interpretive results (Susceptible/Intermediate/Susceptible-dose dependent/Resistant) are provided for specific drug/organism combinations. Results are intended to be used in conjunction with other clinical and laboratory findings. Standard laboratory protocols for processing positive blood cultures should be followed to ensure availability of isolates for supplemental testing as needed. Additionally, subculture of positive blood culture is necessary for the susceptibility testing of organisms present in polymicrobial samples, for testing antimicrobial agents and species not indicated for testing with the device and for epidemiologic testing and for recovery of organisms present in microbial samples. Testing is indicated for Acinetobacter spp., Enterobacterales, Pseudomonas aeruginosa, and Salmonella spp. as recognized by the FDA Susceptibility Test Interpretive Criteria (STIC). The LSGN Kit with LifeScale AST system has demonstrated acceptable performance with the following organisms : • Amikacin: Acinetobacter spp. (A. baumannii complex, A. calcoaceticus, A. lwoffii, A. pittii, A. radioresistens, A. ursingii) • Ampicillin: Enterobacterales (Escherichia coli, Proteus mirabilis), and Salmonella spp. • Aztreonam: Enterobacterales (Citrobacter freundii, Citrobacter koseri, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Serratia marcescens), and Pseudomonas aeruginosa • Cefazolin: Enterobacterales (Escherichia coli, Klebsiella pneumoniae, Klebsiella variicola • Cefepime: Enterobacterales (Citrobacter freundii, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Serratia marcescens), and Pseudomonas aeruginosa • Ceftazidime: Acinetobacter spp. (A. baumannii complex, A. calcoaceticus, A. lwoffii, A. pittii, A. radioresistens), Enterobacterales (Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella variicola, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia stuartii, Serratia marcescens), and Pseudomonas aeruginosa • Ceftazidime-avibactam: Enterobacterales (Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Providencia rettgeri, Providencia stuartii, Serratia marcescens) • Ertapenem: Enterobacterales (Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Providencia rettgeri, Providencia stuartii, Serratia marcescens) • Gentamicin: Enterobacterales (Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella variicola, Serratia marcescens) • Levofloxacin: Enterobacterales (Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Serratia marcescens), and Pseudomonas aeruginosa • Meropenem: Acinetobacter spp. (A. baumannii complex, A. calcoaceticus, A. lwoffii, A. pittii, A. radioresistens, A. ursingii), Enterobacterales (Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Serratia marcescens), and Pseudomonas aeruginosa • Meropenem-vaborbactam: Enterobacterales (Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Providencia rettgeri, Providencia stuartii, Serratia marcescens • Piperacillin-tazobactam: Acinetobacter spp (A. baumannii complex)., Enterobacterales (Citrobacter koseri, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Serratia marcescens), and Pseudomonas aeruginosa, • Trimethoprim-sulfamethoxazole: Enterobacterales (Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, Klebsiella oxytoca, Klebsiella variicola, Morganella morganii, Proteus mirabilis, Proteus vulgaris)

Source page: https://510kreport.com/device/K251875
Methodology: https://510kreport.com/methodology