Time Line of COVID19 :

Day 0: Infected

Day 0 -5:

Asymptomatic phase

Day 5 to 7 :

Onset of symptoms

D0 -D7: Window Period


IN THIS PHASE) – To Prevent Community Spread, Check PCR for all close contacts of Index case, irrespective of symptoms

and Quarantine them,

if positive.


First week Asymptomatic.

Second week – Crucial phase: Clinically Important Symptomatic Stage, when Few Patients may become Critically ill.

Day 14- D21: Third week


D 21- D28: Fourth week

Convalescent Phase


DURING First week:

Only PCR positive

AFTER First week :

After onset ofsymptoms

IgM becomes positive.

(Remains Positive From Day 7- D 21, that is during 2nd and 3rd weeks)

# we can confirm Covid by

Ig M Antibody testing

in All Symptomatic patients.

If Ig M Negative,

Then we can order PCR.

AFTER 2nd Week (Day 14):

IgG becomes positive

(appears by the End of

Second week)

Appearance of Ig G suggests

that the patient is in


(Day 14 -21)


DURING 3rd week(Day 14 -21)

Both Ig M & Ig G are positive.

AFTER 3rd Week (Day 21):

IgM disappears..

Even after Ig M disappears,

patient can be INFECTIVE

Days 1-28:

Throughout Disease course

For 4 weeks..

patient is INFECTIVE :


Antigens will be positive..

As Long as These tests are

positive, patient should be

in Isolation..

AFTER 4 weeks(Day 28):

SARS CoV2 RNA & Antigens disappear and Patients


For Diagnosis of

Active Infection/ INFECTIVITY :

Check SARS CoV2 RNA &

Antigens at anytime..

(all 4 weeks of disease course)

Test for Ig M antibody

in all Symptomatic patients.

If +ve, Confirms Disease.

If -ve, Doesn’t Exclude Disease.

Ig G positivity, suggests –

Decline phase /Past infection.

Isolate them, until they are

PCR Negative

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