Objective: To study the frequency of interstitial 7q deletions in B-cell lymphoproliferative disorders (B-LPDs). Methods: Cases were collected from the clinical laboratory diagnosis database at USLabs/LabCorp over the past two years (2002 to 2004). Cases that showed deletions in the long arm of chromosome 7 were then reviewed. Interstitial deletions in the long arm of chromosome 7 were further investigated according to the indications for clinical laboratory studies and flow cytometry findings. The final clinical diagnosis for each case was obtained from the referring physician. Results: A total of 19 483 cases were included in this series. Eighty-five cases were observed to have either terminal or interstitial deletion in the long arm of chromosome 7. Of the 85 cases, 46 had interstitial deletions accounting for 54.1% of the 7q deletions combined. B-LPDs were found in 10 of the 46 cases, accounting for 21.7%. The B-LPDs associated with 7q interstitial deletions were diverse, including B-cell chronic lymphocytic leukemia (B-CLL) in five cases. The deleted region in the long arm of chromosome 7 in the 10 cases associated with B-LPDs was solely confined to the 7q22-q32 region. Conclusion: (1) The frequency of 7q interstitial deletions associated with B-LPDs is substantially high; (2) 7q interstitial deletions are not uncommon in B-CLL. Objective: To study the frequency of interstitial 7q deletions in B-cell lymphoproliferative disorders (B-LPDs). Methods: Cases were collected from the clinical laboratory diagnosis database at USLabs / LabCorp over the past two years (2002 to 2004). Cases that showed deletions in the long arm of chromosome 7 were then reviewed. Interstitial deletions in the long arm of chromosome 7 were further asked according to the indications for clinical laboratory studies and flow cytometry findings. The final clinical diagnosis for each case was obtained from referring Eighty-five cases were observed to have either terminal or interstitial deletion in the long arm of chromosome 7. Of the 85 cases, 46 had interstitial deletions accounting for 54.1% of the 7q deletions combined. B-LPDs were found in 10 of the 46 cases, accounting for 21.7%. The B-LPDs associated with 7q interstitial deletions were diverse, including The deleted region in the long arm of chromosome 7 in the 10 cases associated with B-LPDs was completely confined to the 7q22-q32 region. Conclusion: (1) The deletion of B-cell chronic lymphocytic leukemia (B-CLL) frequency of 7q interstitial deletions associated with B-LPDs is substantially high; (2) 7q interstitial deletions are not uncommon in B-CLL.