Exhibit 99.3

LABORATORY CORPORATION OF AMERICA HOLDINGS

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

The following unaudited pro forma condensed combined financial information of Laboratory Corporation of America Holdings (“LabCorp”) has been prepared to illustrate the effect of the following items: (i) the consummation of the Agreement and Plan of Merger (the “Merger Agreement”) among LabCorp, Covance Inc., a Delaware corporation (“Covance”), and Neon Merger Sub Inc., a Delaware corporation and wholly owned subsidiary of the Company (“Merger Sub”), pursuant to which Merger Sub will merge with and into Covance (the “Merger”), on the terms and subject to the conditions set forth in the Merger Agreement, with Covance surviving as a wholly owned subsidiary of LabCorp, as described in the Current Report on Form 8-K filed by LabCorp on November 3, 2014; (ii) the issuance of an aggregate of $3,250.0 of senior unsecured notes of LabCorp; and (iii) the incurrence of $1,000.0 of indebtedness by LabCorp under a term loan facility. Under the terms of the Merger Agreement, each outstanding share of Covance common stock at the effective time will be exchanged for $75.76 in cash, without interest, and 0.2686 shares of LabCorp common stock.

The following unaudited pro forma condensed combined financial statements give effect to the Merger under the acquisition method of accounting in accordance with Financial Accounting Standards Board (FASB) Accounting Standard Codification (ASC) Topic 805, Business Combinations, which we refer to as ASC 805, with LabCorp treated as the legal and accounting acquirer. The historical consolidated financial information has been adjusted in the unaudited pro forma condensed combined financial statements to give effect to pro forma events that are (1) directly attributable to the Merger, (2) factually supportable and (3) with respect to the statements of operations, expected to have a continuing impact on the combined results of LabCorp and Covance. Although LabCorp has entered into the Merger Agreement, there is no guarantee that the Merger will be completed. The unaudited pro forma condensed combined balance sheet is based on the individual historical consolidated balance sheets of LabCorp and Covance as of September 30, 2014, and has been prepared to reflect the Merger as if it occurred on September 30, 2014. The unaudited pro forma condensed combined statement of operations for the year ended December 31, 2013 and the nine months ended September 30, 2014 combines the historical results of operations of LabCorp and Covance, giving effect to the Merger as if it occurred on January 1, 2013.

The unaudited pro forma condensed combined statements of operations do not reflect future events that may occur after the Merger, including, but not limited to, the anticipated realization of ongoing savings from operating synergies and certain one-time charges LabCorp expects to incur in connection with the transaction, including, but not limited to, costs in connection with integrating the operations of LabCorp and Covance.

These unaudited pro forma condensed combined financial statements are for informational purposes only. They do not purport to indicate the results that would actually have been obtained had the Merger been completed on the assumed date or for the periods presented, or which may be realized in the future. To produce the pro forma financial information, LabCorp adjusted Covance’s assets and liabilities to their estimated fair values. As of the date of the Registration Statement on Form S-4 of LabCorp filed on November 26, 2014, LabCorp has not completed the detailed valuation work necessary to arrive at the required estimates of the fair value of the Covance assets to be acquired and the liabilities to be assumed and the related allocation of purchase price, nor has it identified all adjustments necessary to conform Covance’s accounting policies to LabCorp’s accounting policies. A final determination of the fair value of Covance’s assets and liabilities will be based on the actual net tangible and intangible assets and liabilities of Covance that exist as of the date of completion of the Merger and, therefore, cannot be made prior to that date. Additionally, the value of the portion of the per share merger consideration to be paid in shares of LabCorp common stock will be determined based on the trading price of LabCorp common stock at the time of the completion of the Merger. Accordingly, the accompanying unaudited pro forma purchase price allocation is preliminary and is subject to further adjustments as additional information becomes available and as additional analyses are performed. The preliminary unaudited pro forma purchase price allocation has been made solely for the purpose of preparing the accompanying unaudited pro forma condensed combined financial statements. The preliminary purchase price allocation was based on reviews of publicly disclosed allocations for other acquisitions in the industry, LabCorp’s historical experience, data that was available through the public domain and LabCorp’s due diligence review of Covance’s business. Until the Merger is completed, both companies are limited in their ability to share information with each other. Upon completion of the

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Merger, valuation work will be performed and any increases or decreases in the fair value of relevant statement of financial position amounts will result in adjustments to the statement of financial position and/or statements of operations until the purchase price allocation is finalized.

There can be no assurance that such finalization will not result in material changes from the preliminary purchase price allocation included in the accompanying unaudited pro forma condensed combined financial statements.

The unaudited pro forma condensed combined financial statements should be read in conjunction with:

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LABORATORY CORPORATION OF AMERICA HOLDINGS AND SUBSIDIARIES

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

Year Ended December 31, 2013

(Dollars in millions except per share data)

See accompanying Notes to Unaudited Pro Forma Condensed Combined Financial Information.

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LABORATORY CORPORATION OF AMERICA HOLDINGS AND SUBSIDIARIES

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

Nine Months Ended September 30, 2014

(Dollars in millions, except per share data)

See accompanying Notes to Unaudited Pro Forma Condensed Combined Financial Information.

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LABORATORY CORPORATION OF AMERICA HOLDINGS

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

As of September 30, 2014

(in millions)

See accompanying Notes to Unaudited Pro Forma Condensed Combined Financial Information.

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NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

(Dollars in millions, except per share data)

1. DESCRIPTION OF TRANSACTION AND BASIS OF PRESENTATION

On November 2, 2014, LabCorp entered into the merger agreement, under the terms of which Covance stockholders as of the effective time will have the right to receive $75.76 in cash, without interest, and 0.2686 of a share of LabCorp common stock for each share of Covance common stock.

LabCorp plans to pay the cash portion of the merger consideration from cash on hand and third party debt financing, which may include some combination of a senior unsecured term loan facility and/or the issuance of senior unsecured notes. LabCorp has entered into a bridge facility commitment letter with Bank of America, N.A., Merrill Lynch, Pierce, Fenner & Smith Incorporated, Wells Fargo Bank, National Association, and Wells Fargo Securities, LLC, which we refer to collectively as the commitment parties. Under the bridge facility commitment letter, the commitment parties have agreed to provide a $4,250.0 senior unsecured bridge term loan credit facility comprised of a $3,850.0 364-day unsecured debt bridge tranche and a $400.0 60-day cash bridge tranche, which we refer to collectively as the bridge facility, to fund part of the cash portion of the merger consideration pursuant to a commitment letter entered into on November 2, 2014, which we refer to as the commitment letter. LabCorp anticipates that some or all of the bridge facility will be replaced prior to the closing of the merger with permanent financing comprised of senior unsecured notes of approximately $3,250.0 with maturities ranging from three to thirty years, which we refer to as the senior unsecured notes, and a term loan facility of $1,000.0, which we refer to as the term loan. LabCorp also expects to replace its existing revolving credit facility with a new revolving credit facility of $1,000.0, which we refer to as the credit facility. For purposes of these pro forma financial statements, management assumed that the cash portion of the merger consideration would be funded by the senior unsecured notes and the term loan, and the bridge facility will not be drawn.

At the effective time, certain shares of Covance restricted stock and deferred stock units will be canceled and converted into the right to receive the merger consideration. This conversion is not expected to result in a significant amount of incremental value to the restricted stock or deferred stock unit holders; however if it is determined that the exchange of such restricted shares or deferred stock units result in incremental value at the acquisition date, LabCorp would recognize a one-time charge for such incremental value as post-combination compensation expense. LabCorp will allocate purchase price consideration of $105.1 for the portion of the fair value of the shares related to pre-combination services (including (i) vested shares and deferred stock units, (ii) shares for which vesting was accelerated as a result of the change in control provision in the 2010 Employee Equity Participation Plan, (iii) deferred stock units for which vesting was accelerated as a result of the change of control provision in the 2012 Directors Deferred Stock Plan and (iv) the portion of the shares for which vesting was accelerated as a result of the merger agreement which related to pre-combination services). LabCorp will recognize post-combination compensation expense of $43.9 as a one-time charge for the portion of the shares for which vesting was accelerated as a result of the change in control provisions in the 2014 Employee Equity Participation Plan and the 2013 Employee Equity Participation Plan, and as a result of the merger agreement which related to services not provided as of the date of the transaction. This post-combination compensation expense has been excluded from the unaudited pro forma condensed combined statement of operations as they reflect charges directly attributable to the merger that will not have a continuing impact on LabCorp’s operations; however, it has been reflected in retained earnings, net of tax of $27.1 on the unaudited pro forma balance sheet.

In addition, outstanding stock options, whether or not vested or exercisable, and outstanding restricted stock units, which we refer to as RSUs, of Covance, which were issued to certain employees of Covance, will be canceled and converted into the right to receive a cash payment upon the closing of the merger. The cash payment for options and Covance RSUs will be calculated at the time of the merger based upon 0.2686 multiplied by the average LabCorp stock price plus cash consideration (less, in the case of each in-the-money Covance stock option, the exercise price of such stock option) multiplied by the number of shares of Covance common stock related to each option and Covance RSU, respectively. The calculated value of the cash payment for purposes of the unaudited pro forma condensed combined financial statement is $38.99 per Covance stock option and RSU based on the closing price of LabCorp’s common stock of $100.95 on November 19, 2014 (the most recent practicable date prior to the filing of the Registration Statement on Form S-4 of LabCorp on November 26, 2014). LabCorp will assume a liability of

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$100.9 for the portion of the cash payments related to pre-combination services (including (i) vested options, and (ii) those options for which vesting was accelerated as a result of the change in control provision in the 2010 Employee Equity Participation Plan). LabCorp will recognize post-combination compensation expense of $1.6 as a one-time charge for the portion of the options for which vesting was accelerated as a result of the change in control provisions in the 2014 Employee Equity Participation Plan and the 2013 Employee Equity Participation Plan, and as a result of the merger agreement. This post-combination compensation expense has been excluded from the unaudited pro forma condensed combined statement of operations as they reflect charges directly attributable to the merger that will not have a continuing impact on LabCorp’s operations; however, it has been reflected in retained earnings, net of tax of $1.0 on the unaudited pro forma balance sheet.

Additionally, certain executive officers of Covance will be eligible to receive change in control payments, including enhanced severance and other separation benefits in the event the executive officer experiences a qualifying termination of employment in conjunction with the completion of the merger. It is estimated that such payments will approximate $23.7, which would be recognized by LabCorp as post-combination compensation expense. This post-combination compensation expense has been excluded from the unaudited pro forma condensed combined statement of operations as they reflect changes directly attributable to the merger that will not have a continuing impact on LabCorp’s operations; however, it has been reflected in retained earnings, net of tax of $9.1 on the unaudited pro forma balance sheet.

The merger is reflected in the unaudited pro forma condensed combined financial statements as being accounted for under the acquisition method in accordance with ASC 805, Business Combination, with LabCorp treated as the acquirer. Under the acquisition method, the total estimated purchase price is calculated as described in Note 3. In accordance with ASC 805, the assets acquired and the liabilities assumed have been measured at fair value based on various preliminary estimates. These estimates are based on key assumptions related to the merger, including reviews of publicly disclosed allocations for other acquisitions in the industry, LabCorp’s historical experience, data that was available through the public domain and LabCorp’s due diligence review of Covance’s business. Due to the fact that the unaudited pro forma condensed combined financial information has been prepared based on preliminary estimates, the final amounts recorded for the merger may differ materially from the information presented herein. These estimates are subject to change pending further review of the fair value of assets acquired and liabilities assumed. In addition, the final determination of the recognition and measurement of the identified assets acquired and liabilities assumed will be based on the fair market value of actual net tangible and intangible assets and liabilities of Covance at the closing date of the merger.

For purposes of measuring the estimated fair value, where applicable, of the assets acquired and the liabilities assumed as reflected in the unaudited pro forma condensed combined financial information, LabCorp has applied the guidance in ASC 820, Fair Value Measurements and Disclosures, which we refer to as ASC 820, which establishes a framework for measuring fair value. In accordance with ASC 820, fair value is an exit price and is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” Under ASC 805, acquisition-related transaction costs and acquisition-related restructuring charges are not included as components of consideration transferred but are accounted for as expenses in the period in which the costs are incurred. For the periods presented, neither LabCorp nor Covance had yet incurred material transaction costs related to the merger.

The unaudited pro forma condensed combined financial statements were prepared in accordance with GAAP in the United States and pursuant to U.S. Securities and Exchange Commission Regulation S-X Article 11, and present the pro forma financial position and results of operations of the consolidated companies based upon the historical information after giving effect to the merger and adjustments described in these footnotes. The unaudited pro forma condensed combined balance sheet is presented as if the merger had occurred on September 30, 2014; and the unaudited pro forma condensed combined statement of operations for the year ended December 31, 2013 and the nine month period ended September 30, 2014 combines the historical results of operations of LabCorp and Covance giving effect to the merger as if it had occurred on January 1, 2013.

The unaudited pro forma condensed combined financial information does not reflect ongoing cost savings that LabCorp expects to achieve as a result of the merger or the costs necessary to achieve these costs savings or synergies.

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2. ACCOUNTING POLICIES AND RECLASSIFICATIONS

LabCorp performed certain procedures for the purpose of identifying any material differences in significant accounting policies between LabCorp and Covance, and any accounting adjustments that would be required in connection with adopting uniform policies. Procedures performed by LabCorp involved a review of Covance’s publicly disclosed summary of significant accounting policies, including those disclosed in Covance’s Annual Report on Form 10-K for the year ended December 31, 2013 and preliminary discussion with Covance management regarding Covance’s significant accounting policies to identify material adjustments. While LabCorp expects to engage in additional discussion with Covance’s management and continue to evaluate the impact of Covance’s accounting policies on its historical results after completion of the merger, LabCorp’s management does not believe there are any differences in the accounting policies of Covance and LabCorp that will result in material adjustments to LabCorp’s consolidated financial statements as a result of conforming Covance’s accounting policies to those of LabCorp.

Additionally, the historical consolidated financial statements of Covance presented herein have been adjusted by condensing certain line items and by reclassifying certain line items in order to conform to LabCorp’s financial statement presentation; these reclassifications are reflected in the column “Reclassifications.”

The reclassification adjustments on the balance sheet pertain to the following: (1) reclassification of intangible assets from other assets; (2) reclassification of tax reserve from other liabilities to deferred income taxes and other tax liabilities; and (3) reclassification of accrued payroll and benefits and income taxes payable to accrued expenses and other. The reclassification adjustments on the statements of operations pertain to the following: (1) reclassification of interest income to investment income; (2) reclassification of reimbursable out of pocket expenses to net sales and cost of sales; (3) reclassification of impairment charges to restructuring and other special charges; (4) reclassification of restructuring costs and other cost actions from selling, general and administrative expenses to restructuring and other special charges; (5) reclassification of gain on sale of investments and gain on sale of businesses to other, net; and (6) reclassification of depreciation expense from amortization of intangibles and other assets to cost of sales ($123.7 and $98.8 for the year ended December 31, 2013 and nine months ended September 30, 2014, respectively) and selling, general and administrative expenses ($3.3 and $2.6 for the year ended December 31, 2013 and nine months ended September 30, 2014, respectively).

3. PRELIMINARY CONSIDERATION TRANSFERRED AND PRELIMINARY FAIR VALUE OF NET ASSETS ACQUIRED

The merger has been accounted for using the acquisition method of accounting in accordance with ASC 805, which requires, among other things, that the assets acquired and liabilities assumed be recognized at their acquisition date fair values, with any excess of the consideration transferred over the estimated fair values of the identifiable net assets acquired recorded as goodwill. In addition, ASC 805 establishes that the common stock issued to effect the merger be measured at the closing date of the merger at the then-current market price. Based on (1) the closing price of LabCorp’s common stock of $100.95 per share on November 19, 2014 (the most recent practicable date prior to the filing of the Registration Statement on Form S-4 of LabCorp filed on November 26, 2014), (2) the fair value of Covance’s indebtedness, paid off in conjunction with the merger (3) the number of shares of Covance common stock outstanding as of November 19, 2014 (the most recent practicable date prior to the filing of the Registration Statement on Form S-4 of LabCorp filed on November 26, 2014), and (4) the number of options to purchase Covance common stock, restricted stock, restricted stock units and deferred stock units that are outstanding at October 31, 2014 as disclosed in the merger agreement, the total consideration would have been approximately $6,304.4. Changes in the share price of LabCorp’s common stock, or changes in the number of Covance’s outstanding shares of common stock, stock options or Covance RSUs outstanding could result in material differences in the consideration and, thus, the purchase price and related purchase price allocation. At the effective time, each outstanding share of Covance common stock will be cancelled and converted into the right to receive (1) $75.76 in cash, without interest, and (2) 0.2686 of a share of LabCorp common stock.

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The following is a preliminary estimate of the consideration to be paid by LabCorp in the merger:

The estimated value of the consideration does not purport to represent the actual value of the total consideration that will be received by Covance’s stockholders when the merger is completed. In accordance with US GAAP, the fair value of the equity securities issued as part of the consideration will be measured at the closing date of the merger at the then-current market price. This requirement will likely result in a per share value component different from the $100.95 per share on November 19, 2014 assumed in the calculation, and that difference may be material. For example, an increase or decrease of 10% in the price of LabCorp’s common stock on the closing date of the merger from the price of LabCorp stock assumed in these unaudited pro forma condensed combined financial statements would change the value of the consideration by approximately $154.4, which would be reflected as an equivalent increase or decrease to goodwill.

The following is a summary of the preliminary estimated fair values of the net assets acquired:

LabCorp has made preliminary allocation estimates based on limited access to information and will not have sufficient information to make final allocations until after completion of the merger. The final determination of the purchase price allocation is anticipated to be completed as soon as practicable after completion of the merger. LabCorp anticipates that the valuations of the acquired assets and liabilities will include, but not be limited to net working capital, property, plant, and equipment, trade names and trademarks, customer relationships and residual goodwill. The valuations will consist of physical appraisals, discounted cash flow analyses, or other appropriate valuation techniques to determine the fair value of the assets acquired and liabilities assumed.

For purposes of these unaudited pro forma condensed combined financial statements and the preliminary purchase accounting allocation, management assumed that the $862.2 carrying value of Covance’s property, plant and

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equipment at September 30, 2014, approximated its fair value. Upon closing of the merger, LabCorp will record the acquired property, plant and equipment at its acquisition date fair values. At the date of the Registration Statement on Form S-4 of LabCorp filed on November 26, 2014, LabCorp had limited access to information and did not have sufficient information, such as the specific nature, age, condition or location of the land, buildings, machinery and equipment, and does not know the appropriate valuation premise to make a preliminary valuation. A fair value increase or decrease of 10% would increase or decrease property, plant and equipment by $86.2, deferred tax liability by approximately $33.0 and goodwill by approximately $53.2. With other assumptions held constant, a 10% increase in the fair value adjustment for property, plant and equipment would increase annual pro forma depreciation expense by approximately $12.7.

The final consideration, and amounts allocated to assets acquired and liabilities assumed in the merger could differ materially from the preliminary amounts presented in these unaudited pro forma condensed combined financial statements. A decrease in the fair value of assets acquired or an increase in the fair value of liabilities assumed in the merger from those preliminary valuations presented in these unaudited pro forma condensed combined financial statements would result in a dollar-for-dollar corresponding increase in the amount of goodwill that will result from the merger. In addition, if the value of the acquired assets is higher than the preliminary indication, it may result in higher amortization and depreciation expense than is presented in these unaudited pro forma condensed combined financial statements.

4. PRELIMINARY PRO FORMA ADJUSTMENTS RELATED TO THE MERGER

The preliminary pro forma adjustments included in the unaudited pro forma condensed combined financial statements related to the merger are as follows:

The preliminary amortization expense for the intangible assets acquired from Covance is as follows:

The estimated fair value of amortizable intangible assets is expected to be amortized on a straight-line basis over the estimated useful lives. The amortizable lives reflect the periods over which the assets are expected to provide material economic benefit. With other assumptions held constant, a 10% increase in the fair value adjustment for amortizable intangible assets would increase annual pro forma amortization by approximately $9.2. In addition, with other assumptions held constant, a one year change in the estimated useful lives of the customer list and tradenames and trademarks would change annual amortization expense by approximately $2.5 and $1.2, respectively.

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The final terms of the senior unsecured notes and term loan will be subject to market conditions and may change materially from the assumptions described below. Depending upon the nature of the changes, the impact on the unaudited pro forma condensed combined financial statements could be material.

The pro forma adjustment to interest expense reflects the additional interest expense that would have been incurred during the historical periods presented assuming the merger and the issuance of the senior unsecured notes and term loan had occurred as of January 1, 2013.

An increase (decrease) of 0.125% in the assumed interest rate of the term loan would increase (decrease) annual pro form interest expense by $1.3. An increase (decrease) of 0.125% in the assumed weighted average interest rate of the senior unsecured notes would increase (decrease) annual pro forma interest expense by $4.1. An increase (decrease) of $100.0 in the principal amount of the senior unsecured notes would increase (decrease) annual pro forma interest expense by $3.8.

If LabCorp were to use the bridge facility of $4,250.0 (instead of the senior unsecured notes and term loan as assumed), the pro forma interest expense would be $93.5 for the year ended December 31, 2013 and $70.1 for the nine months ended September 30, 2014. An increase (decrease) of 0.125% in the assumed interest rate on the bridge facility would increase annual pro forma interest expense by $5.3.

Debt issuance costs estimated to be incurred in conjunction with the merger have been amortized over the term of the respective debt instrument for the purposes of calculating the net pro forma adjustment to interest expense.

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As all outstanding shares of Covance common stock will be eliminated in the merger, the unaudited pro forma weighted average number of basic shares outstanding is calculated by adding LabCorp’s historical weighted average number of basic shares outstanding for the period and the number of shares of LabCorp common stock expected to be issued to Covance’s stockholders in the merger. The unaudited pro forma weighted average number of diluted shares outstanding is calculated by adding LabCorp’s historical weighted average number of diluted shares outstanding for the period and the number of shares of LabCorp common stock expected to be issued in the merger. As each outstanding stock option or RSU issued under each of the Covance Employee Equity Participation Plans, whether or not then vested or exercisable, will be canceled and terminated at the effective time in exchange for the right to receive cash, such stock options and RSUs were excluded from this calculation. Refer to pro forma footnote Note 1 for more information about treatment of stock-based compensation under the provisions of the merger agreement.

Components of the adjustment include (i) a decrease in cash resulting from payment of the cash component of the merger consideration; (ii) a decrease in cash related to the payment to holders of Covance restricted stock, restricted stock units, deferred stock units and stock options, of which $178.2 relates to merger consideration and $33.9 is to be recognized as post-combination compensation expense; (iii) a decrease in cash related to the repayment of Covance’s debt, including accrued interest; (iv) estimated transaction related expenses of $306.8, consisting of financing fees of $46.8, of which an estimated $29.7 will be capitalized, and advisory costs of $260.0, expected to be expensed as incurred in connection with the merger; (v) estimated change in control payments, including enhanced severance and other separation benefits that are payable upon a qualifying termination of employment in conjunction with the completion of the merger in an amount of approximately $23.7 and (vi) an increase in cash resulting from the proceeds in additional borrowings of $3,250.0 of senior unsecured notes and an aggregate amount of $1,000.0 for the term loan.

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The preliminary unaudited pro forma adjustment to additional paid in capital is calculated as follows:

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The preliminary unaudited pro forma adjustment to retained earnings is calculated as follows:

The estimated fees and expenses and post-combination compensation expense associated with the payment of accelerated equity awards and change in control payments have been excluded from the unaudited pro forma condensed combined statements of operations as they reflect charges directly attributable to the merger that will not have a continuing impact on LabCorp’s operations.

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