Subsequent Injury Benefit Trust Fund (SIBTF)
Turning Complex Claims Into Compelling Cases
SIBTF claims are among the most technically demanding matters in California workers’ compensation — requiring precise impairment ratings, thorough apportionment analysis, and meticulous documentation of pre-existing conditions. At Expedient Medicolegal Services, we give attorneys the medical-legal infrastructure to pursue these claims with confidence.
What Is SIBTF?
The Subsequent Injuries Benefits Trust Fund (SIBTF) provides additional compensation to injured workers who had a pre-existing disability or impairment and later sustain a work-related injury that, in combination, results in a significantly greater level of overall disability.
Qualifying and substantiating these claims demands:
- Careful documentation of pre-existing impairments
- Accurate apportionment analysis
- Precise Whole Person Impairment (WPI) ratings
- Compliance with evolving statutory and regulatory requirements
With ongoing legislative changes shaping how SIBTF claims are evaluated, our providers stay current to ensure every report meets the latest evidentiary standards.
Our Services
We provide end-to-end support for SIBTF matters, including:
Pre-Qualification Case Screening
- Identification of cases that may meet SIBTF thresholds
- Early-stage strategy to support claim viability
Comprehensive Medical-Legal Evaluations
- Detailed assessment of prior and subsequent injuries
- Accurate impairment rating and apportionment analysis
Record Review & Case Strategy Support
- Evaluation of medical records to support SIBTF eligibility
- Guidance aligned with current legal standards and proposed legislative changes
QME/AME Coordination
- Access to qualified evaluators experienced in SIBTF matters
- Reports structured to withstand legal scrutiny
Meet Our SIBTF Medical Director
Dr. C. K. Mak, DC, CCSP, DABCA, QME, EMT
Medical Director | SIBTF
Dr. Chun Keung Mak is a California-licensed Chiropractic Physician since 2007 and Qualified Medical Evaluator since 2012, with focused SIBTF evaluation experience since 2017. A graduate of Southern California University of Health Sciences, Dr. Mak has built his practice around complex musculoskeletal disability, cumulative trauma, and multi-factorial impairment analysis.
Beyond his clinical role, Dr. Mak serves in senior advisory and quality assurance capacities within the QME space — reviewing and standardizing medico-legal reports across multiple specialties. This experience gives him a precise understanding of what makes reports defensible, where cases tend to break down, and how to structure opinions that hold up under deposition and judicial scrutiny.
His SIBTF evaluations focus on establishing threshold eligibility under Labor Code § 4751, identifying qualifying pre-existing disability, and clearly articulating the overlap and synergistic effects between prior and subsequent conditions. Reports integrate large-volume record review, objective findings, and precise application of the AMA Guides (5th Edition), with detailed apportionment analysis pursuant to Labor Code §§ 4663 and 4664.
Dr. Mak is particularly effective in cases involving incomplete or fragmented records — where early identification of missing documentation and strategic record development can materially impact case viability. He remains actively engaged with evolving SIBTF standards, including ongoing developments under AB 1329, ensuring his evaluations reflect current expectations and the heightened scrutiny this area demands.
