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Long-read sequencing 

Comprehensive Analysis of Thalassemia Alleles (CATSA)

The World’s First Complete, IVD-Certified LRS Technology Transfer Solution 

The Challenges of Thalassemia Detection

Because of the diverse spectrum of thalassemia and related hemoglobinopathies variants, no single test has previously been able to detect them all. PCR assays and short-read NGS often fail to detect structural and rare variants, leading to step-wise testing, missed carriers, and genetically unresolved cases.​​​

Limitations of Conventional Test

Hematological Test

  • Complete blood count and capillary electrophoresis often lack sensitivity for carrier screening

  • Missing silent carriers with α⁺-thalassemia, β⁺-thalassemia, and α-triplicate

PCR-based Test

  • Typically target only hotspot variants

  • Over a thousand variants are associated with thalassemia, yet most PCR panels cover only a few dozen

Short-read NGS

  • Often miss large structural variants (such as large deletions, triplicates), miscall some variants, and fail to provide phasing information

Pink Poppy Flowers

​A Ultimate Thalassemia Clinical Solution 

Comprehensive Analysis of Thalassemia Alleles (CATSA) resolves these challenges with an efficient, standardized workflow. Powered by advanced long-read sequencing (PacBio SMRT sequencing), CATSA reliably detects over 2,200 known thalassemia, hemoglobinopathies, and hemoglobin variants, including rare and structural types, while maintaining low failure rates.

 

This all-in-one assay consolidates fragmented testing to deliver timely, accurate results for physicians, making it an ideal solution for screening and diagnosis in diverse and isolated populations.

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Expert consensus officially endorsed as a diagnostic and screening tool by the Medical Genetics Branch of the Chinese Medical Doctor Association (2025)

Comparison

Variant
PCR-method
NGS
CATSA

α-thal Deletions

Few
Few
>100 (with HS40)

α-thal HBA1/2 SNVs/InDels

Few
Few
903

α-thal Structural Variants

May be misinterpreted as deletions
✕
5

δβ-thal Deletions

✕
Few
>50

δβ-thal HBB SNVs/InDels

Few
Hundreds
1135

δβ-thal HBD SNVs/InDels

✕
✕
160

δβ-thal Structural Variants

✕
Difficult
2

Differentiate homologous genes (HBA1 vs HBA2, HBB vs HBD)

✕
Partial
✔

Phasing

✕
✕
✔
Performance backed by published data

Backed by over 50 peer-reviewed publications, CATSA consistently demonstrates superior accuracy and clinical utility in real-world scenarios.​

  • 20+ novel variants identified

  • 100% accuracy¹

A total of 1,759 blood samples with abnormal hemoglobin parameters were collected across 10 centers to compare CATSA with a standard PCR panel.¹

Compare with NGS 

  • CATSA has 100% accuracy compared to NGS miscalls in both HBA1/2 and HBB genes, driving a 2.28% improvement in overall detection yield²

NGS (full-length HBA1/2 and HBB) and CATSA were simultaneously performed for 1,122 individuals in Hainan Province.²

  • Versus a 13.7% NGS error rate (missed triplications and HKαα miscalls as deletions), CATSA delivered 100% accuracy across all α-thalassemia carriers³

A total of 2,926 participants were retrospectively enrolled in Shanghai for carrier screening of 5 diseases using both commercial NGS carrier screening panel and LRS panels, with CATSA applied for thalassemia.³

Prenatal Case Study - compare with PCR

In a multi-center retrospective study of 278 at-risk amniotic fluid samples, CATSA:

  • Outperformed PCR panel by corrected the results in 15 samples (5.4%)

  • Reclassified the predicted phenotype severity in 8 fetuses (2 cases from Trait to Intermedia, and 1 from Intermedia to Trait).

These insights directly influenced pregnancy management and counseling.⁴​

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Comprehensive coverage

Covers the most types of thalassemia and hemoglobinopathy variants

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The new gold standard

Improves detection rate compared with routine test with >99.9% accuracy

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Proven at scale

With 350,000+ cases and 50+ publications

​Xcelom Limited and Berry Genomics provide a comprehensive end-to-end technology transfer solution for conducting clinical tests within your facility.

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From Sample to Report:

  • Laboratory setup and consultation

  • End-to-end Workflow: SOPs, reagent, and training 

  • Analysis Software: From sample management to report generation

CATSA IVD solution

Platform

PacBio Vega, Sequel II, and Sequel IIe system

Sample Type

gDNA from dried blood spot, blood, buccal swab, and amniotic fluid

Test per Batch

Max. 384 Tests per SMRT Cell (Mixed Batching Supported)

Operation Time

~ 77 hours (Hand on time: ~10.5 hours)

Automation Capability

Yes

Coverage

Targets full-length of HBA1/2, HBB-HBD, and HS-40 regions

Covers > 2,200 clinically relevant variants

Resources

References:

1. Liang Q, Gu W, Chen P, et al. A More Universal Approach to Comprehensive Analysis of Thalassemia Alleles (CATSA). J Mol Diagn. 2021;23(9):1195-1204.

2. Huang R, Liu Y, Xu J, et al. Back-to-Back Comparison of Third-Generation Sequencing and Next-Generation Sequencing in Carrier Screening of Thalassemia. Arch Pathol Lab Med. 2024;148(7):797-804.

3. Li S, Hua R, Han X, et al. Targeted long-read sequencing facilitates effective carrier screening for complex monogenic diseases including spinal muscular atrophy, α-/β-thalassemia, 21-hydroxylase deficiency, and fragile-X syndrome. J Transl Med. 2025;23(1):307.

4. Liang Q, He J, Li Q, et al. Evaluating the Clinical Utility of a Long-Read Sequencing-Based Approach in Prenatal Diagnosis of Thalassemia. Clin Chem. 2023;69(3):239-250.

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