-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 Gfuw0J8BLGJlvqTD/dF4R55y7/PFBk56SypIyJA6b7zMfhYjs5HxOcwFQJope55t
 NCwOjIfSDCXh5P5ZOivetA==

<SEC-DOCUMENT>0001239724-03-000007.txt : 20030610
<SEC-HEADER>0001239724-03-000007.hdr.sgml : 20030610
<ACCEPTANCE-DATETIME>20030610102029
ACCESSION NUMBER:		0001239724-03-000007
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030521
FILED AS OF DATE:		20030610

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			THOMPSON W LEIGH MD PHD
		CENTRAL INDEX KEY:			0001234367

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23017
		FILM NUMBER:		03738304

	BUSINESS ADDRESS:	
		STREET 1:		C/O LA JOLLA PHARMACEUTICAL CO
		STREET 2:		6455 NANCY RIDGE DRIVE
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		8586466649

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SONTRA MEDICAL CORP
		CENTRAL INDEX KEY:			0001031927
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
		IRS NUMBER:				411649949
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		58 CHARLES STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		6174945337

	MAIL ADDRESS:	
		STREET 1:		58 CHARLES STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CHOICETEL COMMUNICATIONS INC/MN/
		DATE OF NAME CHANGE:	20020701

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SONTRA MEDICAL CORP
		DATE OF NAME CHANGE:	20020701

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CHOICETEL COMMUNICATIONS INC /MN/
		DATE OF NAME CHANGE:	19970625
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-05-21</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001031927</issuerCik>
        <issuerName>SONTRA MEDICAL CORP</issuerName>
        <issuerTradingSymbol>&quot;SONT&quot;</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001234367</rptOwnerCik>
            <rptOwnerName>THOMPSON W LEIGH MD PHD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeSecurity>
        <securityTitle>
            <value>Stock option-right to buy</value>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>2.3</value>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2003-05-21</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>A</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>17500</value>
            </transactionShares>
            <transactionValue>
                <value>0</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>2003-05-21</value>
            <footnoteId id="F1"/>
        </exerciseDate>
        <expirationDate>
            <value>2013-05-21</value>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>Common stock</value>
            </underlyingSecurityTitle>
            <underlyingSecurityShares>
                <value>17500</value>
            </underlyingSecurityShares>
        </underlyingSecurity>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>67500</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </derivativeSecurity>

    <footnotes>
        <footnote id="F1">100% of the shares are exercisable on 5/21/03</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Sean Moran for W. Leigh Thompson, MD, PhD</signatureName>
        <signatureDate>2003-06-10</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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