Data Integrity in Analytical Laboratories
Data integrity in analytical laboratories means keeping testing information complete, consistent and accurate throughout its lifecycle.
A passing result is only useful when the laboratory can show how it was obtained.
This guide explains the controls behind reliable QC records, follows a failed system suitability sequence, and examines data handling risks in LC-MS and NMR.
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Why data integrity matters in pharmaceutical laboratories
Pharmaceutical and chemical analytical laboratories generate the evidence used to assess material and product quality. Within pharmaceutical Quality Control (QC), accurate, complete and reliable records support decisions about compliance with specifications, batch disposition and patient safety. A result loses credibility when the laboratory cannot trace it to the sample, test conditions, original observations and review that produced it [1] [3].
In its 2018 guidance, FDA reported increased findings of data integrity violations during CGMP inspections and described regulatory actions including warning letters and import alerts. These findings explain why the reliability of laboratory records receives close attention during an inspection [1].
Weak quality culture, ineffective leadership, inadequate procedures, limited software knowledge and poorly controlled technology can leave opportunities for errors or misconduct. Deadline pressure can encourage shortcuts when staff do not feel able to report a problem. Management should provide workable processes, training and a culture that encourages prompt reporting and investigation. Technical controls and management oversight need to work together [1] [2].
ALCOA principles and complete laboratory records
In short: A complete record includes original evidence, the full testing history and the metadata needed to review it.
ALCOA describes five qualities of a trustworthy record: attributable, legible, contemporaneous, original and accurate. In a laboratory, that means identifying who performed the work, keeping the record readable, documenting it when the activity occurs, preserving the original evidence or an appropriate true copy, and checking that the record correctly represents the work [1] [2].
ALCOA+ adds complete, consistent, enduring and available. Failed and repeated tests belong in the testing history; timestamps and sequences should make sense; records should remain protected and retrievable throughout retention. A true copy must preserve the meaning and required metadata of the original. Where dynamic functionality is needed to reconstruct or evaluate the analysis, a static printout alone may be insufficient [1] [2].
For US finished-pharmaceutical CGMP, 21 CFR 211.194 requires complete laboratory data, including test methods, instrument graphs and spectra, calculations, results and second-person review. ICH Q7 section 6.6 addresses laboratory control records for active pharmaceutical ingredients. 21 CFR Part 11 governs applicable electronic records and signatures; it does not replace these underlying record requirements. The requirements that apply depend on the regulated activity and jurisdiction [3] [7] [9].

Read the checklist as text
ALCOA+ data integrity checklist for QC laboratories
Nine qualities of a trustworthy laboratory record. ALCOA: the core five. ALCOA+: four additions.
- Attributable
- Who did it, and who changed it
- Legible
- Readable now and later
- Contemporaneous
- Recorded as the work happens
- Original
- Original data or a true copy
- Accurate
- Matches the work performed
- Complete
- Failed and repeat runs included
- Consistent
- Times and sequence add up
- Enduring
- Protected through retention
- Available
- Retrievable for review and inspection
Can an independent reviewer reconstruct the result?
Based on FDA Data Integrity and Compliance With Drug CGMP Q&A (2018) and MHRA GxP Data Integrity Guidance (2018, updated 2021).
How small shortcuts become data integrity concerns
A shared password, an undocumented trial injection, a deleted analytical run or an unjustified manual integration can remove information needed to assess a result. A shortcut that appears to save a few minutes may leave no dependable account of who did the work or why data changed. Poor understanding of laboratory software can compound this problem [1] [4].
More serious examples include fabricating data, copying results and presenting them as new measurements, or backdating an analysis to misrepresent when it occurred. Weak access controls, missing audit trail reviews and investigation conclusions without supporting evidence can allow such problems to persist. These practices must be investigated on their facts; a discrepancy alone does not establish deliberate misconduct [1] [2].
A failed sequence that must stay visible
Hypothetical sequence
Consider a hypothetical assay sequence that fails system suitability. To save time, the analyst aborts the sequence, flushes the system and restarts the analysis. The repeat passes. The analyst does not report the first failure to the supervisor or document it, and completes the record as though only the successful sequence had occurred.
Months later, an inspector finds the aborted sequence in the instrument audit trail and asks for its explanation. The laboratory has no contemporaneous account, investigation or recorded reason for repeating the test. The supervisor's earlier review also failed to identify the missing sequence. Reporting only the successful run presents an incomplete testing history.
The passing repeat does not resolve the omission. Retain the original data, document the event when it occurs, notify the responsible person, and investigate the cause under the approved procedure. Record the reason for any repeat and review the relevant sequence, processing history and audit trail before accepting the result. The initial failure does not itself prove the final result is wrong, but its exclusion prevents a defensible review [1] [4].
Data manipulation and selective reporting
Testing a sample repeatedly until it passes, while ignoring, excluding or deleting unsuccessful results, creates a misleading picture of the analysis. FDA's laboratory controls guidance specifically addresses unofficial trial injections of product samples. A product sample cannot be used to see whether it will pass and then disappear from the official testing record [4].
During a review or inspection, instrument and server data can be compared with laboratory notebooks, worksheets and final reports, with IT support where necessary. This reconciliation can identify runs that have no corresponding explanation, results copied between records, or gaps between acquisition and reporting. Preserve and investigate discrepancies instead of assuming that a complete-looking report represents the entire analysis [1] [3].
Failed, repeated and invalidated runs must remain traceable, with the reason for invalidation and any investigation retained. Excluding a result from the final calculation requires scientific justification; it does not authorize destruction of the original evidence. Incomplete records can undermine confidence in the laboratory's controls and support regulatory findings [1] [3].
Audit trail review and changes to standard weight
In short: Review critical changes alongside the associated record before final approval.
An audit trail is a secure, computer-generated, time-stamped history that supports reconstruction of record creation, modification and deletion. It can show who changed a critical value, when the change occurred and the recorded reason. Its usefulness depends on the system being appropriately configured, protected and reviewed; software should not be assumed to capture every action merely because an audit trail feature exists [1] [2].
QA personnel, supervisors and designated reviewers need to examine relevant changes and resolve unexplained entries. FDA recommends reviewing trails for changes to critical data with the associated record, before final approval. The review frequency follows the underlying record requirements; where no frequency is specified, a documented risk assessment should guide it. Disabled audit trails or ineffective review leave gaps in oversight, but one missed change does not establish that a trail was disabled [1].
Instrument date and time controls
Instrument and computer timestamps establish when testing and changes took place. Changing a system clock to make a sample appear to have been analysed within its approved stability window misrepresents the testing history. The apparent time of analysis can no longer demonstrate that the sample met the applicable timing requirement [1] [2].
Reviewers should assess whether users can alter date and time settings and whether changes require authorization, justification and a traceable record. Restrict access to these settings, control approved adjustments and verify time consistency across connected systems. An authorized clock correction is different from concealed backdating, but both the adjustment and its impact on affected records need to be understandable [1] [2].
User privileges and access rights
Analysts should have the permissions needed for their assigned work. Giving someone both routine testing access and unrestricted administrative control creates opportunities to change processing methods, system configurations or records without adequate oversight. The relevant question is what the role can do and how those actions are controlled [1].
FDA recommends that system administration, including permissions such as deleting files or changing configurations, be assigned independently of responsibility for record content. Routine analyst work should use an appropriately restricted account. Define roles, document authorized users' permissions, review access and ensure consequential changes receive appropriate authorization and review [1].
Human errors and deliberate misconduct
Incomplete or inaccurate documentation, improper sample handling and failure to record an activity at the time can compromise the reliability of laboratory evidence. Such problems may arise from unintentional mistakes; deliberate fabrication or concealment can also occur. Both need investigation, although their causes and corrective actions may differ [1] [2].
Assess training, procedures, workload, supervision and system design alongside the individual event. Correct the record transparently, evaluate affected results and address the cause. A conclusion of human error should be supported by the investigation and should not stop the review of underlying system weaknesses. ALCOA principles provide a practical basis for examining what went wrong [1] [2].
Data handling in LC-MS laboratories
In short: Keep the raw data, processing decisions and carryover assessment traceable to the result.
Liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) can generate complex datasets with several acquisition and processing steps. Their analytical capabilities do not remove the need for a complete record. Review must connect the raw data, processing decisions and reported result [2] [5] [6].
In LC-MS, baseline drift and signal interference can complicate automatic peak integration. Manual integration may be scientifically justified, but changing a baseline or peak boundary simply to obtain a passing value is not acceptable. Preserve the original data, processing settings, justification, revised result and review so that another scientist can assess the effect of the adjustment [1].
Carryover is another concern. Material from a concentrated sample can persist in parts of the injection system, column or MS source and contribute signal in a subsequent blank or sample. Sensitive LC-MS methods can detect small residual amounts, which may inflate a later result.
Blank responses should be assessed against method-specific acceptance criteria; an absolute zero signal is not a universal criterion. Investigate the source, assess affected injections and document corrective action and any justified reanalysis. Ignoring a known interference can make reporting unreliable, but observing carryover alone does not demonstrate manipulation [5].
Data handling in NMR laboratories
In short: Preserve the FID files and processing history so the displayed spectrum can be reconstructed.
Retaining only a processed NMR spectrum can leave the reviewer without the evidence needed to reconstruct processing. Preserve the original free induction decay (FID) files, acquisition metadata, processing parameters and reported spectra for regulated analyses. The raw record allows another scientist to examine how the displayed spectrum was produced [2] [6].
Unusual settings or changes confined to one spectral region warrant examination; they do not by themselves prove an attempt to conceal an impurity. Complete raw data, justified processing and documented review make it possible to distinguish an acceptable correction from a change that distorts the result. These controls preserve confidence in both LC-MS and NMR reporting [1] [2].
Five controls reviewers can test
- Reconcile the complete testing history. Include failed, aborted, repeated and invalidated runs and check their explanations against the final report.
- Examine relevant audit trail entries. Resolve unexplained changes to weights, integration parameters, methods, sample identities or sequence order.
- Check individual attribution. Verify who acquired, changed and reviewed data, and whether their permissions fit their responsibilities.
- Check chronology. Confirm that timestamps and authorized clock adjustments support the recorded sequence of events and applicable sample stability limits.
- Reconstruct the reported result. Retain raw files, metadata, processing versions, investigation evidence and review records needed to explain the final value.
A practical release question
Before accepting an analytical result, ask whether an independent reviewer can reconstruct the full path from sample and instrument to reported value, including failed runs, changes and reasons for repeat testing. If the answer is no, resolve the record gap and assess its impact before relying on the result for a quality decision. Use this review framework with the site's approved procedures and applicable requirements.
Frequently asked questions
What are the 5 principles of data integrity?
The five ALCOA principles are attributable, legible, contemporaneous, original and accurate. They mean that records identify who did the work, remain readable, are recorded when the activity happens, preserve original evidence or a suitable true copy, and correctly represent the activity [1] [2].
What is data integrity in the pharma industry?
Data integrity is the completeness, consistency and accuracy of data throughout its lifecycle. In pharmaceutical laboratories, it allows reviewers to trace a result to the sample, method, raw data, changes and approval. Reliable records support product quality decisions and help protect patients [1] [3].
What are the FDA guidelines for data integrity?
FDA's 2018 guidance, Data Integrity and Compliance With Drug CGMP: Questions and Answers, explains its expectations for reliable records, metadata, audit trails, access controls and review. Read it alongside applicable CGMP regulations, including 21 CFR 211.194, and Part 11 where applicable. Guidance explains FDA's thinking; the underlying regulations contain binding requirements [1] [3] [9].
What are the four main types of data integrity?
In database terminology, four common categories are entity integrity, referential integrity, domain integrity and user-defined integrity. These concern unique records, valid links between records, permitted values and organization-specific rules. They can support laboratory information systems, while ALCOA and ALCOA+ describe broader expectations for pharmaceutical records [8] [2].
What is the difference between ALCOA and ALCOA+?
ALCOA covers attributable, legible, contemporaneous, original and accurate records. ALCOA+ adds complete, consistent, enduring and available, emphasizing the full testing history, logical sequence, durable retention and access to records when needed [2].
How often should laboratory audit trails be reviewed?
FDA recommends reviewing audit trails for changes to critical data with the associated record and before final approval. Frequency follows the applicable review requirements for that record. Where no frequency is specified, use a documented risk assessment and an approved procedure [1].
Is manual integration a data integrity violation?
Manual integration is not automatically a violation. It needs a scientific justification, retained original data and processing history, and appropriate review. An undocumented adjustment or one made simply to turn a failing result into a passing result raises a data integrity concern [1].
Can a laboratory delete a failed or aborted run after a repeat passes?
A passing repeat does not justify deleting the earlier CGMP test data. Retain the original record and document the failure, investigation, reason for repeat and review. If a result is invalidated, keep the evidence and justification for that decision [1] [4].
References
- FDA, Data Integrity and Compliance With Drug CGMP: Questions and Answers (2018).
- MHRA, Guidance on GxP Data Integrity (2018, updated 2021).
- 21 CFR 211.194, Laboratory Records.
- FDA, Questions and Answers on CGMP Laboratory Controls, question 17.
- Hughes et al., Determination of carryover and contamination for mass spectrometry-based chromatographic assays (2007).
- Sengupta and Weljie, NMR Spectroscopy-Based Metabolic Profiling of Biospecimens (2019).
- ICH Q7, Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients, section 6.6.
- IBM, What is Data Integrity? (database terminology).
- 21 CFR Part 11, Electronic Records and Electronic Signatures.