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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 IoCqwnKklRQG8V9vWHRUjPziCrQ674qWKldUAcXE6ppuwbmss2kRk2As/em6QlNi
 vYJgPODkA3wf1n/SskCIuw==

<SEC-DOCUMENT>0001239724-04-000013.txt : 20040527
<SEC-HEADER>0001239724-04-000013.hdr.sgml : 20040527
<ACCEPTANCE-DATETIME>20040527104249
ACCESSION NUMBER:		0001239724-04-000013
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040526
FILED AS OF DATE:		20040527

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PUORRO GERARD E
		CENTRAL INDEX KEY:			0001236578

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23017
		FILM NUMBER:		04833919

	BUSINESS ADDRESS:	
		STREET 1:		CANDELA CORP
		STREET 2:		530 BOSTON POST RD
		CITY:			WAYLAND
		STATE:			MA
		ZIP:			01778
		BUSINESS PHONE:		5083587400

	FORMER NAME:	
		FORMER CONFORMED NAME:	PUORRO GERALD E
		DATE OF NAME CHANGE:	20030528

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>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-05-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001236578</rptOwnerCik>
            <rptOwnerName>PUORRO GERARD E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SONTRA MEDICAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>10 FORGE PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>FRANKLIN</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02038</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-05-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.99</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option-Right to Buy</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.99</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-05-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-05-19</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2014-05-19</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">100% of the shares were exercisable as of May 19,2004.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Gerard E.Puorro</signatureName>
        <signatureDate>2004-05-27</signatureDate>
    </ownerSignature>
</ownershipDocument>

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