ADULT SYPHILIS SURVEILLANCE STAGING WHEN PRIMARY OR SECONDARY SYPHILIS SIGNS/SYMPTOMS ARE PRESENT

(Not to be used as guidance for treatment)

START HERE:

Current* clinicianobserved chancre?

Clinician-observed signs 

clinically compatible 

with secondary syphilis 

such as: rash, mucous 

patches, condylomata

lata, alopecia?

Clinician-observed signs 

clinically compatible 

with secondary syphilis 

such as: rash, mucous 

patches, condylomata

lata, alopecia?

yes

no

T. pallidum directly

detected? (Darkfield

microscopy OR PCR)

NOT a Primary or 

Secondary Syphilis case.

Refer to flowchart for 

Adult Syphilis Surveillance 

Staging When Primary 

or Secondary Signs/

Symptoms NOT Present

T. pallidum directly

detected? (Darkfield

microscopy OR PCR)

STAGE AS: Primary 

Syphilis†

CASE STATUS: 

Confirmed

Reactive nontreponemal 

(VDRL or RPR) OR 

Reactive treponemal 

(e.g., TP-PA, EIA) 

test results?

yes

no

yes

no

NOT a case

NOT a case yes

no

yes

no

*Current refers to the anchoring date of the original diagnosis, such as at time of original clinical diagnosis or positive screening test.

†Neurologic, ocular, and otic manifestations of syphilis can occur at any stage. After assigning syphilis stage, assess all cases for these clinical manifestations and classify

separately as “No,” “Verified,” “Likely,” “Possible,” or “Unknown.” Late clinical manifestations of syphilis are classified separately as “No,” “Verified,” “Likely,” or 

“Unknown.” For assistance with classification of these manifestations, please see clinical manifestations algorithms.

ACRONYMS: T. pallidum = Treponema pallidum; PCR = polymerase chain reaction; VDRL = Venereal Disease Research Laboratory; RPR = rapid plasma reagin; 

TP-PA = Treponema pallidum particle agglutination; EIA = enzyme immunoassay

RESOURCES: Syphilis case definitions; Syphilis treatment guidelines; Partner services

CS328736-A

yes

no

Reactive nontreponemal 

(VDRL or RPR) AND

Reactive treponemal 

(e.g., TP-PA, EIA) 

test results?

STAGE AS: 

Secondary Syphilis†

CASE STATUS: 

Confirmed

STAGE AS: 

Primary Syphilis†

CASE STATUS: 

Probable

STAGE AS: 

Secondary Syphilis†

CASE STATUS: 

Probable

yes

no

Updated 6/1/2023
START HERE:

Clinician-observed 

primary or secondary 

syphilis signs 

currently* present?

Refer to flowchart 

for Adult Syphilis 

Surveillance Staging 

When Primary or 

Secondary Syphilis 

Signs/Symptoms 

Are Present

*Current refers to the anchoring date of the original diagnosis, such as at time of original clinical diagnosis or positive screening test.

†Neurologic, ocular, and otic manifestations of syphilis can occur at any stage. After assigning syphilis stage, assess all cases for these clinical manifestations and classify

separately as “No,” “Verified,” “Likely,” “Possible,” or “Unknown.” Late clinical manifestations of syphilis are classified separately as “No,” “Verified,” “Likely,” or “Unknown.”

For assistance with classification of these manifestations, please see clinical manifestations algorithms.

ACRONYMS: VDRL = Venereal Disease Research Laboratory; RPR = rapid plasma reagin; TP-PA = Treponema pallidum particle agglutination; EIA = enzyme immunoassay.

RESOURCES: Syphilis case definitions; Syphilis treatment guidelines; Partner services

CS328736-A

yes

no

NOT a case

Documented 

prior history 

of syphilis 

diagnosis?

≥4-fold increase in 

nontreponemal test titer during 

the previous 12 months (and 

no evidence that increase was 

not sustained for >2 weeks)?

yes

no

Documented seroconversion 

of a nontreponemal test during 

the previous 12 months?

STAGE AS: 

Early Non-primary

Non-secondary Syphilis†

CASE STATUS: 

Probable

yes

Documented seroconversion 

of a treponemal test during the 

last 12 months?

STAGE AS: 

Early Non-primary

Non-secondary Syphilis†

CASE STATUS: 

Probable

≥4-fold increase in nontreponemal test 

titer from the last nontreponemal test titer 

>12 months ago (and no evidence

increase was not sustained for >2 weeks)?

NOT a new case

yes

Sexual exposure to partner 

with primary, secondary, 

or early non-primary 

non-secondary syphilis 

within previous 12 months?

no

Only sexual 

contact (sexual 

debut) occurred 

within the previous 

12 months?

History of signs/symptoms consistent 

with primary or secondary syphilis 

during the previous 12 months?

STAGE AS: 

Unknown Duration 

or Late Syphilis†

CASE STATUS:

Probable

yes

no

Reactive 

nontreponemal 

(VDRL or RPR)

AND Reactive 

treponemal 

(e.g., TP-PA, EIA)

test results?

ADULT SYPHILIS SURVEILLANCE STAGING WHEN PRIMARY OR SECONDARY SIGNS/SYMPTOMS NOT PRESENT

(Not to be used as guidance for treatment)

yes

no

yes

Clinical signs/symptoms and 

laboratory results that meet the likely 

or verified criteria for neurologic, 

ocular, otic, and/or late clinical 

manifestations of syphilis?

no

no

yes

no

Updated 6/1/2023

no

yes

yes

no

no

yes
START HERE:

Is this a case 

of syphilis?

Reactive serologic 

nontreponemal 

AND treponemal 

test results?

*Any case with clinical signs/symptoms and laboratory results that meet the likely or verified criteria for neurologic, ocular, otic, or late clinical manifestations of syphilis and that has no

evidence of having acquired the disease within the preceding 12 months meets the Council of State and Territorial Epidemiologists case definition for unknown duration or late syphilis.

†Clinician input may be needed to rule out other possible causes.

§The Council of State and Territorial Epidemiologists case definition for neurologic manifestations of syphilis defines elevated CSF protein as >50 mg/dL and elevated CSF WBC

count as >5 WBCs/mm3. Additional guidance for interpretation of CSF results is available in CDC’s STI Treatment Guidelines.

¶Because ocular manifestations are considered signs/symptoms clinically compatible with neurosyphilis, cases classified as having ocular manifestations should also be classified

as having neurologic manifestations.

ACRONYMS: CSF = cerebrospinal fluid; VDRL = Venereal Disease Research Laboratory; WBC = white blood cell; T. pallidum = Treponema pallidum; PCR = polymerase chain reaction

RESOURCES: Syphilis case definitions; Syphilis treatment guidelines; Partner services

CS328983-A

yes

no

yes

Signs/symptoms 

clinically compatible 

with neurosyphilis 

(without other 

known cause†)?

yes

Reactive CSF VDRL 

test result in the 

absence of grossly 

bloody CSF 

contamination?

yes

CLASSIFY AS: NO neurologic 

manifestations

Elevated§ CSF 

protein or WBC 

count (without other 

known cause†)?

yes

no

no no

no

START HERE:

Is this a case 

of syphilis?

yes

no

SURVEILLANCE CLASSIFICATION OF OCULAR MANIFESTATIONS OF SYPHILIS (Not to be used as guidance for treatment)

SURVEILLANCE CLASSIFICATION OF NEUROLOGIC MANIFESTATIONS OF SYPHILIS (Not to be used as guidance for treatment)

CLASSIFY AS: YES, VERIFIED 

neurologic manifestations

CLASSIFY AS: YES, LIKELY 

neurologic manifestations

CLASSIFY AS: YES, POSSIBLE 

neurologic manifestations

Reactive serologic 

nontreponemal 

AND treponemal 

test results?

yes

Signs/symptoms 

clinically compatible 

with ocular syphilis 

(without other 

known cause†)?

yes

Demonstration of T. pallidum

in aqueous or vitreous fluid 

by darkfield microscopy, or 

by PCR or equivalent direct 

molecular methods?

yes

CLASSIFY AS: NO ocular 

manifestations

Exam findings by an 

ophthalmologist consistent

with ocular syphilis (without

other known cause†)?

yes

no

no no

no

CLASSIFY AS: 

YES, VERIFIED 

ocular manifestations¶

CLASSIFY AS: YES, LIKELY 

ocular manifestations¶

CLASSIFY AS: YES, POSSIBLE 

ocular manifestations¶

Neurologic 

manifestations of syphilis 

should only be assigned 

to cases of syphilis*

Ocular manifestations 

of syphilis should only 

be assigned to cases 

of syphilis*

Updated 5/23/2023
START HERE:

Is this a case 

of syphilis?

*Any case with clinical signs/symptoms and laboratory results that meet the likely or verified criteria for neurologic, ocular, otic, or late clinical manifestations of syphilis and that has no

evidence of having acquired the disease within the preceding 12 months meets the Council of State and Territorial Epidemiologists case definition for unknown duration or late syphilis.

†Clinician input may be needed to rule out other possible causes.

§Because otic manifestations are considered signs/symptoms clinically compatible with neurosyphilis, cases classified as having otic manifestations should also be classified as having

neurologic manifestations.

ACRONYMS: T. pallidum = Treponema pallidum; PCR = polymerase chain reaction

RESOURCES: Syphilis case definitions; Syphilis treatment guidelines; Partner services

CS328983-A

yes

no

SURVEILLANCE CLASSIFICATION OF OTIC MANIFESTATIONS OF SYPHILIS (Not to be used as guidance for treatment)

Otic manifestations of 

syphilis should only be 

assigned to cases 

of syphilis*

Reactive serologic 

nontreponemal 

AND treponemal 

test results?

yes

Signs/symptoms

clinically compatible 

with otosyphilis

(without other 

known cause†)?

yes

Demonstration of T. pallidum 

in inner ear fluid by darkfield 

microscopy, or by PCR or 

equivalent direct molecular 

methods?

yes

CLASSIFY AS: NO otic 

manifestations

Exam findings by an

otolaryngologist consistent 

with otosyphilis (without 

other known cause†)?

yes

no

no no no

CLASSIFY AS: 

YES, VERIFIED 

otic manifestations§

CLASSIFY AS: 

YES, LIKELY 

otic manifestations§

CLASSIFY AS: 

YES, POSSIBLE 

otic manifestations§

Updated 5/23/2023
*Any case with clinical signs/symptoms and laboratory results that meet the likely or verified criteria for neurologic, ocular, otic, or late clinical manifestations of syphilis and that has no

evidence of having acquired the disease within the preceding 12 months meets the Council of State and Territorial Epidemiologists case definition for unknown duration or late syphilis.

†Additional information about characteristic lesions associated with late clinical manifestations of syphilis is available in CDC’s STI Treatment Guidelines.

§Clinician input may be needed to rule out other possible causes.

¶Please see syphilis surveillance case definitions and neurologic manifestations classification algorithm for additional assistance.

ACRONYMS: CV = cardiovascular; T. pallidum = Treponema pallidum; PCR = polymerase chain reaction

RESOURCES: Syphilis case definitions; Syphilis treatment guidelines; Partner services

CS328983-A

START HERE:

Is this a case 

of syphilis?

yes

no

Characteristic CV, skin, 

bone, or other tissue 

abnormalities/lesions†

(without other known 

cause§) with demonstration 

of T. pallidum in lesions by 

special stains or equivalent 

methods, PCR or equivalent 

direct molecular methods, 

or pathologic changes 

consistent with T. pallidum

infection on histologic 

examination of lesions?

SURVEILLANCE CLASSIFICATION OF LATE CLINICAL MANIFESTATIONS OF SYPHILIS (Not to be used as guidance for treatment)

Clinical signs/

symptoms consistent 

with late neurologic 

manifestations of 

syphilis AND

meets criteria¶ for 

verified neurologic 

manifestations 

of syphilis?

yes

no

yes

Late clinical 

manifestations of 

syphilis should only 

be assigned to cases 

of syphilis*

Reactive serologic 

nontreponemal 

AND treponemal 

test results?

Characteristic CV, 

skin, bone, or other 

tissue abnormalities/ 

lesions† (without other 

known cause§)? 

Clinical signs/symptoms 

consistent with late 

neurologic manifestations of 

syphilis AND meets criteria¶

for likely neurologic 

manifestations of syphilis?

no

no

CLASSIFY AS: 

YES, VERIFIED 

late clinical manifestations

CLASSIFY AS: 

YES, LIKELY 

late clinical manifestations

CLASSIFY AS: NO late 

clinical manifestations

Updated 5/23/2023

yes

yes

no

yes

CLASSIFY AS: NO late 

clinical manifestations

no