RELEASE

Exhibit 10.1

RELEASE

▇▇▇▇▇, ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Stowe IX, L.P
and the other purchasers listed on Schedule I attached hereto ("Purchasers")

Gentlemen:

LabOne, Inc., a Delaware corporation, for and in consideration of Ten Dollars ($10.00) and other valuable consideration, the receipt whereof is hereby acknowledged, hereby releases and forever discharges the Purchasers from their obligations under Section 6.02(f) of the Securities Purchase Agreement between the Purchasers and LabOne, Inc., dated as of August 31, 2001, this Release to be effective as of May 20, 2002.

LabOne, Inc.

By /s/ W. ▇▇▇▇▇▇ ▇▇▇▇▇
W. ▇▇▇▇▇▇ ▇▇▇▇▇
President and Chief Executive Officer

SCHEDULE I

WCAS MANAGEMENT CORPORATION

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