Clinical NGS Workflow Compliance, Step by Step
Beginner resources such as Illumina's NGS workflow overview walk through the basic NGS workflow: nucleic acid extraction, library preparation, sequencing, and data analysis and interpretation. Many training resources also call out cluster generation or template amplification as a distinct step between library prep and sequencing. In a clinical lab each step carries regulatory obligations. SLC has no relationship with Illumina; this page maps the general workflow to CLIA and CAP expectations.
SLC is an independent, nationwide clinical laboratory consulting network. We are not affiliated with, authorized by or endorsed by any sequencing platform maker, kit supplier or accrediting organization.
Before step 1: specimen and extraction
Specimen acceptance criteria, chain of identity, nucleic acid quantity and quality records (42 CFR 493.1241-1242 pre-analytic systems).
Step 1: Library preparation
Controls per batch, reagent lot tracking, library QC acceptance criteria, contamination controls. Library prep guide.
Step 2: Cluster generation / template preparation
Loading concentration, instrument maintenance and function checks, and records of consumable lots. On non-cluster platforms the analogous step is template prep or flow cell loading.
Step 3: Sequencing
Run acceptance using lab-defined metrics established during validation (yield, quality scores, pass-filter rates, control performance). Instrument maintenance logs. Run QC metrics.
Step 4: Data analysis
Validated, version-locked pipeline; sample-level QC (coverage, contamination, identity); interpretation and report review. Pipeline validation.
Documentation across the workflow
Procedure manual (493.1251), QC records (493.1256), test records and retention (493.1105), corrective action, and director review.
Competency for each step
Assess wet-lab and bioinformatics personnel using direct observation, monitoring of recording and reporting, review of worksheets and QC, maintenance performance, blind or previously tested samples, and problem-solving assessment.
Pre-analytic phase in detail
CLIA's pre-analytic requirements cover test requests, specimen submission, handling and referral (42 CFR 493.1241 and 493.1242). For NGS, the requisition should capture the information needed for interpretation, such as indication, family history for germline tests, or tumor type and tumor content for somatic tests. Specimen acceptance criteria should define minimum volume or tissue amount, acceptable fixatives and anticoagulants, maximum transport time and temperature, and conditions for rejection or testing with a disclaimer. For tissue, a pathologist review of tumor content and marking for macrodissection is a key step.
Extraction and nucleic acid QC
Record the extraction method, instrument, reagent lots, operator and yield for every sample. Measure concentration with a fluorometric method and purity by spectrophotometry where useful, and assess integrity for FFPE or RNA. Set acceptance limits during validation and define what happens when a sample falls short: re-extract, request new specimen, or proceed with a documented limitation.
Run setup and sample identity
Errors in index assignment or sample loading can attach the wrong result to a patient. Use electronic sample sheets generated from the LIS where possible, verify plate maps with a second person, and confirm sample identity downstream with sex checks, SNP fingerprinting against an independent assay, or other identity checks your validation supports. Document each check.
Analytic run acceptance
Each run should be accepted or rejected against written criteria before sample-level review: run-level output and quality metrics, control sample performance, and absence of contamination in negative controls. Each sample is then reviewed for coverage of required regions, quality and identity checks. Record who reviewed and when. Rejected runs or samples follow a documented path to repeat testing.
Post-analytic phase
Interpretation, report review and sign-out are where clinical meaning is added. Define who can interpret and sign, the variant classification method, second review rules for significant findings, report content, critical result communication, and how corrected reports are issued. CLIA's test report requirements in 42 CFR 493.1291 apply.
Ongoing quality assessment
Monitor turnaround time, run and sample failure rates, repeat rates, QC trends, PT or alternative assessment results, and corrected reports. Review them at a set interval, record conclusions and corrective actions, and use the data when evaluating changes.
How SLC helps
SLC maps your NGS workflow step by step to CLIA and CAP requirements, writes the SOPs and forms for each step, defines run and sample acceptance processes, and builds competency assessments for wet-lab and bioinformatics staff. Plans from $500.
Instrument maintenance and function checks
CLIA requires maintenance and function checks at least at the frequency the manufacturer specifies (42 CFR 493.1254). Sequencers, thermal cyclers, liquid handlers, fluorometers and fragment analyzers all have maintenance schedules. Log daily, weekly and periodic tasks, wash cycles, and service visits, and verify performance after major repairs before returning to clinical use.
Reagent and lot management
Label reagents with receipt and open dates, store them as specified, and track lot numbers for every batch. Before putting a new lot of a critical reagent such as an enrichment panel or library kit into use, run a lot-to-lot comparison with a known sample and document acceptance.
Competency for each workflow role
CLIA's six competency elements apply to testing personnel: direct observation of routine testing; monitoring recording and reporting of results; review of intermediate results, worksheets and QC; direct observation of maintenance and function checks; testing previously analyzed specimens, internal blind samples or PT samples; and assessment of problem-solving skills. Map them to each NGS role, from extraction technologist to bioinformatician and variant analyst.
Personnel structure
High-complexity NGS testing requires a qualified laboratory director, technical supervisor, clinical consultant, general supervisor and testing personnel under Subpart M. Clarify which steps are performed by testing personnel and document their qualifications and training.
Sequencing and template preparation records
For each run, record the instrument, flow cell or chip lot, reagent cartridge lots, loading concentration, run parameters and operator. Keep run reports or summaries as part of the test record. If a run is aborted or repeated, document why and what was done.
Data analysis records
For each sample, record the pipeline version, reference build, analysis date, QC results and who reviewed them. Link these to the final report so any result can be traced back to its data and analysis conditions.
Mapping summary
Specimen and extraction: 493.1241, 493.1242 pre-analytic requirements
Procedures: 493.1251 procedure manual
Equipment: 493.1254 maintenance and function checks
Validation: 493.1253 performance specifications
QC: 493.1256 control procedures
Reports: 493.1291 test report
Records: 493.1105 retention
Personnel: Subpart M; competency per 493.1451 and 493.1413 as applicable
Referral and send-out steps
If any part of the workflow is performed elsewhere, such as sequencing at another CLIA-certified laboratory or analysis by a vendor, define responsibilities in writing, confirm the other lab's certification where required, and keep records showing which lab performed which step. 42 CFR 493.1242 addresses referral of specimens, and the report must identify the laboratory that performed the test where required by 493.1291.
Building the compliance binder
Organize documents by workflow step: requisition and specimen requirements, extraction, library prep, sequencing, analysis, interpretation and reporting. Under each, file the SOP, validation section, QC criteria and recent records. Inspectors can then follow a sample from receipt to report quickly.
Software: compliance tracking with myLabCompliance
Paper binders and spreadsheets break down once a lab runs multiple instruments, shifts and testing personnel. We recommend myLabCompliance, a web-based CLIA compliance management platform for technical consultants, lab directors, lab owners and quality teams. Its public site describes tools for personnel management, validation, quality control, equipment, document control, scheduling, analytics and audit-ready workflows.
QC logs and quality control records kept in one place
Personnel records and competency tracking
Validation records for new instruments and methods
Equipment records for maintenance and calibration
Document control for SOPs and policies
Scheduling for recurring tasks such as PT events and competency
More NGS resources from SLC
Frequently asked questions
Does each NGS step need QC?
Yes; the lab defines and documents QC and acceptance criteria for pre-analytic, analytic and post-analytic steps.
Is SLC affiliated with Illumina?
No.
Sound Lab Consultants (SLC), PO Box 2135, Chandler, AZ 85244. A nationwide clinical laboratory consulting network. Plans from $500.