Reanalysis of Genomic Data
What Is Reanalysis of Genomic Data?
Reanalysis of genomic data is a fresh clinical review of previous genetic test data using updated scientific knowledge, improved analytical methods, and current medical context. It is particularly relevant when an earlier result was negative, uncertain, or incomplete, but the underlying DNA data may still hold clinically useful information.
Unlike repeat testing, reanalysis usually works with existing sequencing data such as WES or WGS rather than collecting a new sample. This allows a specialist clinical geneticist to revisit the original findings in light of new gene-disease associations, refined variant classifications, and any changes in the patient’s phenotype over time.
At London Genetics, this process is used to help identify diagnoses that may have been missed initially and to support more accurate clinical decision-making. For patients exploring broader testing options, our genetic testing services provide the foundation for both initial diagnosis and later reinterpretation when new evidence emerges.
Why Reanalysis Matters in Clinical Genetics
Reanalysis of genomic data matters because our understanding of genes, variants, and disease is constantly improving. A result that was once negative or uncertain may become clinically meaningful when new gene-disease links are discovered, variant classifications are updated, or a patient’s symptoms develop over time. This makes reanalysis of genomic data an important part of modern clinical genetics, especially for individuals who previously had WES or WGS with no clear diagnosis.
This process can help turn an unresolved genetic test result into a more useful clinical answer. It may identify a variant that was previously unknown, clarify the significance of a variant of uncertain significance, or connect earlier findings with a more complete medical picture. In some cases, reanalysis of genetic data can support a new diagnosis, improve risk assessment for family members, and guide better long-term care decisions.
For patients considering genetic testing for the first time, our genetic testing services provide the starting point for both diagnosis and future re-evaluation when additional evidence becomes available. Reanalysis is especially valuable when the original test was performed some time ago, when the clinical picture has changed, or when the original report did not provide a definitive answer.
In short, reanalysis of genomic data matters because genetics is not static. As medical knowledge advances, previous test data can often be revisited to produce new and clinically relevant insights.
Who Should Consider Reanalysis?
Reanalysis of genomic data may be suitable for individuals whose previous genetic testing did not provide a clear diagnosis or whose clinical circumstances have changed. It is particularly valuable when existing WES or WGS data can be reviewed using updated genomic knowledge and current clinical information.
Patients with an Undiagnosed Condition
Reanalysis may be appropriate if you have ongoing symptoms or a suspected inherited condition but your previous genetic test did not identify a definitive cause.
Individuals with Negative or Inconclusive Results
If earlier whole exome sequencing or whole genome sequencing produced a negative, uncertain, or inconclusive result, new scientific evidence may allow the existing data to be interpreted differently.
Patients with New or Evolving Clinical Features
Changes in symptoms, the development of additional medical features, or a revised clinical diagnosis can provide important information for a more targeted reanalysis of genetic data.
Families Affected by an Inherited Condition
Reanalysis can be useful when a family history suggests an inherited disorder, particularly if previous testing did not explain the condition or identify a clear pattern of inheritance.
People Whose Test Was Performed Some Time Ago
Genomic databases, disease knowledge, and laboratory interpretation methods continue to develop. Individuals tested several years ago may benefit from reviewing their existing results in light of these advances.
Reanalysis is not the same as repeating a genetic test. It involves reviewing existing genomic data and may not require a new sample. If you are unsure whether reanalysis is appropriate, our genetic testing services and specialist clinical assessment can help determine the most suitable next step.
How We Reanalyse Existing Genomic Data
At London Genetics, reanalysis is a rigorous clinical process led by our Consultant Clinical Geneticist. We do not simply re-run software; we integrate your raw genomic data with the latest medical science to provide meaningful, actionable answers.
First, we securely access your existing sequencing data—typically from a previous WES or WGS order—ensuring it is technically compatible with our current analytical pipelines. Once the data is retrieved, our team applies the most recent reference databases, which are updated regularly to reflect new gene-disease associations and refined variant classification criteria.
The technical reanalysis focuses on identifying variants that were previously missed or deemed uncertain. However, the most critical phase is the clinical interpretation. We cross-reference the genomic findings with your current clinical history, including recent symptoms, imaging, and biochemical reports. This ensures that the genetic profile matches the patient’s actual health status and clinical presentation.
Because these findings can have significant implications for you and your relatives, we place a strong emphasis on professional guidance. Every reanalysis concludes with a detailed review session, which you can explore through our genetic counselling services. This ensures you fully understand what the findings mean for your health management and future care decisions.
This meticulous approach is especially vital for complex cases, including those often managed within our paediatric genomics service, where accurate identification of rare variants can be life-changing for developing patients. By combining advanced bioinformatics with expert medical judgment, we aim to transform previously inconclusive data into clear, actionable clinical guidance.
Which Tests Are Suitable for Reanalysis?
Not all genetic tests are candidates for reanalysis. The primary requirement for an effective reanalysis of genomic data is that the original test generated raw sequence data, typically through High-Throughput Sequencing (HTS). The most suitable tests for this service are Whole Exome Sequencing (WES) and Whole Genome Sequencing (WGS), as these platforms produce the comprehensive, deep-coverage datasets necessary for a successful secondary review.
If your previous testing was focused on identifying the root cause of Inherited Disorders & Rare Genetic Conditions, these datasets are often prime candidates for re-evaluation. Because these tests examine thousands of genes simultaneously, they contain a wealth of information that can be re-interrogated as new medical evidence and gene-disease associations emerge.
We also frequently perform reanalysis on data from Pharmacogenomics studies. As our understanding of how DNA influences drug metabolism and treatment response evolves, re-examining your pharmacogenomic profile can sometimes reveal new insights into which medications are most effective or safe for you, even if previous reports were inconclusive or limited in scope.
Furthermore, for those who previously underwent carrier screening or prenatal assessments, our reproductive genetics services can sometimes utilise earlier genomic data to clarify reproductive risk profiles. While small-scale, targeted tests—such as single-gene sequencing or specific mutation panels—are generally not suitable for broad genomic reanalysis due to the limited nature of the raw data, modern sequencing-based assays often provide enough depth to uncover new, actionable details.
If you are unsure whether your previous reports or data files are suitable for genetic test reanalysis, our team can securely review your existing documentation to assess whether the original data quality and format are sufficient to proceed with a more advanced interpretation.
What New Findings May Be Identified?
Reanalysis of existing genomic data can sometimes reveal clinically significant findings that were not identified in the original report. As genetic knowledge grows, variants that were once classified as uncertain or unrelated to disease may later become important.
Hover over each box to explore the types of findings that may emerge during re-analysis.
Previously Missed Pathogenic Variants
Variants Reclassified as Likely Pathogenic
New Gene-Disease Associations
Additional Explanations for Unresolved Symptoms
Reanalysis does not repeat the original test — it reinterprets the existing genomic data using updated scientific knowledge. This can increase diagnostic yield without requiring a new sample.
Clinical Benefits of Reanalysis
The clinical value of reanalysis of genomic data lies in its ability to turn previously inconclusive results into actionable findings. In many cases, the original test may not have provided a definitive diagnosis, not because the condition was not genetic, but because the available evidence at the time was incomplete. As genomic medicine advances, reanalysis offers a powerful opportunity to revisit existing data with updated knowledge, improved interpretation frameworks, and more sophisticated analytical tools.
One of the principal clinical benefits is the potential to achieve a diagnosis without repeat testing. This is particularly important for patients who have already undergone extensive investigations, especially those with complex inherited conditions, rare disorders, or unresolved developmental concerns. By using existing WES or WGS data, reanalysis can identify variants that were previously missed, reclassify variants of uncertain significance, or reveal new gene-disease associations that were not yet established when the original analysis was performed.
This process may also improve clinical management. A more precise genetic diagnosis can guide treatment choices, inform surveillance strategies, and support personalised care planning. In some cases, reanalysis may also clarify recurrence risk for family members, making it especially relevant in the context of Genetic Counselling and Reproductive Genetics. For children and families affected by unresolved developmental or neurological symptoms, it may also complement the work of our Paediatric Genomics service.
Another important advantage is that reanalysis supports more efficient use of genomic data already collected. Rather than repeating the same test, clinicians can extract additional value from an existing dataset, improving diagnostic yield while reducing unnecessary delays and additional sampling. This is particularly useful for individuals who have already undergone testing through our Genetic Testing pathway or who are being assessed for Inherited Disorders & Rare Genetic Conditions.
In short, the clinical benefits of reanalysis of genomic data extend beyond diagnosis alone. It can contribute to more informed care, better family counselling, and a more complete understanding of an individual’s genetic condition.
Why Choose London Genetics?
Choosing the right provider for reanalysis of genomic data is an important decision. At London Genetics, we combine clinical expertise, up-to-date genomic knowledge, and a patient-centred approach to help you understand whether your existing genetic data may provide further answers.
Our team reviews previous genetic reports and available data to determine whether reanalysis is appropriate. We consider the type of test performed, the quality and format of the available data, your current medical history, and any changes in your symptoms or family history since the original analysis.
We use current scientific evidence, updated gene–disease associations, and recognised variant interpretation guidelines when reviewing genomic data. This may help identify findings that were not understood or clinically significant at the time of the original test. However, we provide clear and balanced information and do not guarantee that reanalysis will result in a diagnosis.
Our service is also designed to avoid unnecessary repeat testing where suitable genomic data already exists. If further investigation is recommended, our team can explain the available options and help you understand the next steps. You may also benefit from our Genetic Screening service if your clinical or family history indicates that additional testing should be considered.
Every case is reviewed individually. We explain the potential benefits, limitations, and possible outcomes before proceeding, helping you make an informed decision about your care. Where appropriate, the results can be discussed alongside our Genomic Medicine services to support a broader understanding of your health.
If you have had previous WES, WGS, or another sequencing-based genetic test and would like to know whether your data may offer new insights, contact London Genetics to discuss whether reanalysis of genomic data may be suitable for you.
Reanalysis vs Repeat Testing
Reanalysis of genomic data and repeat genetic testing are different approaches. Understanding the distinction can help you choose the most appropriate next step after an inconclusive or outdated result.
| Feature | Reanalysis of Genomic Data | Repeat Genetic Testing |
|---|---|---|
| What It Involves | A new review and interpretation of existing genomic data using current scientific knowledge. | A new genetic test performed on a fresh sample, such as blood or saliva. |
| Is a New Sample Required? | Usually no, provided that the original raw data is available and suitable for review. | Yes. A new sample is normally required for the laboratory to perform another analysis. |
| Main Purpose | To look for new interpretations, updated variant classifications, or recently recognised gene-disease associations. | To generate new genetic data or investigate areas that were not covered by the original test. |
| When It May Be Suitable | When previous WES, WGS, or sequencing data is available but the original result was inconclusive or based on older knowledge. | When the original test did not include the relevant genes, the data is unavailable, or a different testing method is clinically indicated. |
| Potential Clinical Value | May improve diagnostic yield and provide further insight without repeating the original laboratory process. | May identify genetic changes that were not captured or detectable through the previous test. |
| Limitations | It cannot identify information that was not captured in the original dataset, and a diagnosis is not guaranteed. | It may involve additional cost, time, and sample collection, and may not be necessary if suitable data already exists. |
Our team can review your previous genetic reports and available data to help determine whether reanalysis or repeat testing is the more appropriate option for your circumstances.
How to Request Reanalysis
If you already have genetic test results, requesting reanalysis of genomic data is usually a simple process. Our team can review your previous findings and help determine whether your existing data is suitable for a fresh clinical interpretation.
Initial Clinical Review
The process begins with a consultation with one of our Consultant Clinical Geneticists. During this appointment, we review your previous report, discuss your symptoms and family history, and assess whether reanalysis of genomic data may provide additional value in your case.
Sharing Previous Test Information
If you have had WES, WGS, or another sequencing-based genetic test, we may ask you to provide the original report and any available raw data. This allows us to check whether the file format and data quality are appropriate for reanalysis using current interpretation standards.
Understanding the Outcome
Once the review is complete, we explain the findings clearly and discuss any relevant next steps. In some cases, reanalysis may identify a more meaningful result, while in others it may confirm that further testing or specialist follow-up is needed.
If you would like to find out whether your previous genetic test could be reinterpreted, book a consultation with our clinical genetics team to discuss reanalysis of genomic data and the most suitable next step.
Book a ConsultationIn this section you can check frequently asked questions.
Will reanalysis of genomic data guarantee a diagnosis?
While reanalysis significantly increases the chances of finding an answer, it does not guarantee a new diagnosis. The success of the process depends on factors such as the quality of the original data, the type of test previously performed, and the current state of medical knowledge regarding your specific symptoms. Our clinicians will discuss the likelihood of finding new information with you during your initial consultation.
What if I do not have a copy of my original genetic test data?
In the UK, patients generally have a legal right to access their medical records, including their genetic test results and raw data. If you do not have a copy, you can contact the laboratory or the clinic that performed the original test to request your reports and raw data files. If you are unsure how to proceed, our team can provide guidance on what to ask for.
How long does the reanalysis process take?
Once we have securely received and verified your existing genomic data, the reanalysis process typically takes a few weeks. This timeframe allows our bioinformatics team to perform a thorough review against the latest gene-disease databases and clinical literature. We will provide you with a clear timeline during your initial consultation.
How old can my genetic test data be to be suitable for reanalysis?
There is no strict “expiry date” for genomic data. However, the technology used in the original test matters more than the age of the data. High-Throughput Sequencing (HTS) data, such as Whole Exome (WES) or Whole Genome Sequencing (WGS), from several years ago is often still highly valuable and can be re-evaluated using modern interpretation tools and updated scientific evidence.
Is reanalysis of genomic data better than repeating the test?
Not necessarily “better,” but often more efficient. Reanalysis is a cost-effective and patient-centred alternative to repeat testing because it uses data that you already have, saving the time and effort required for new sampling. However, if your original test was limited in scope or if new technologies have significantly improved the detection of your specific condition, our clinicians may recommend repeat testing instead.
Does my GP need to refer me for this service?
No, you do not need a GP referral to access our genetic test reanalysis service at London Genetics. You can initiate the process by booking a direct consultation with one of our Consultant Clinical Geneticists. We will handle the clinical review and guide you through every step of the process.
