HIV diagnosis - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
USMLE Articles
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam

Thread Tools Search this Thread Display Modes
Old 12-13-2011
USMLE Forums Veteran
Steps History: Not yet
Posts: 281
Threads: 74
Thanked 131 Times in 68 Posts
Reputation: 141
Question HIV diagnosis

Why is that P24 arises early in HIV but it takes some time for Gp 120 and gp41 to rise untill the end of window period.

Also why do we do PCR diagnosis in a neonate,can we not to P24 in that case as well

one of my friends took the exam and he had a q related to the first part of my query.
Reply With Quote Quick reply to this message
The above post was thanked by:
zohaib (12-13-2011)

Old 12-13-2011
USMLE Forums Master
Steps History: 1+CK+CS+3
Posts: 790
Threads: 76
Thanked 671 Times in 316 Posts
Reputation: 689
Thumbs Up answer for 2nd question

Diagnosis of HIV infection in infants is aided by HIV culture or DNA/RNA polymerase chain reaction (PCR); positive results are confirmed by repeating the test. In suspected cases, HIV testing should occur in the newborn period (ie, before the infant is 48 h old), at age 1-2 months, and again at age 3-6 months. Testing at age 14 days may allow for earlier detection of HIV in infants who had negative test results within the first 48 hours of life. By approximately age 1 month, PCR testing has a 96% sensitivity and 99% specificity to identify HIV.

The 2010 Panel on Antiretroviral Therapy and Medical Management of HIV-Infected Children[29] recommendations for diagnosing infants are as follows:

Because of the persistence of the maternal HIV antibody, infants younger than 18 months require virologic assays that directly detect HIV in order to diagnose HIV infection
Preferred virologic assays include HIV DNA PCR and HIV RNA assays
Virologic diagnostic testing is recommended at birth in infants at high risk of HIV infection (eg, infants born to HIV-infected mothers who did not receive prenatal care or prenatal antiretroviral therapy or who had HIV viral loads ≥1,000 copies/mL close to time of delivery)
Further virologic testing in infants with known perinatal HIV exposure is recommended at 14-21 days, at 1–2 months, and at 3–6 months.
An antibody test to document seroreversion to HIV antibody–negative status in uninfected infants is recommended at age 12–18 months
In children 18 months and older, HIV antibody assays can be used for diagnosis

The Panel does not recommend use of the currently approved HIV p24 antigen assay for infant diagnosis in the United States because the sensitivity and specificity of the assay in the first months of life is less than that of other HIV virologic tests.

Within the first 48 hours, 14 days, and 4 weeks of life, 38%, 93%, and 96% of infected children, respectively, have positive HIV DNA PCR results. Any positive HIV DNA PCR finding should be confirmed with follow-up HIV DNA PCR before infection is diagnosed.

HIV infection can be ruled out if one of the following is true:

DNA HIV PCR results are consistently negative in an infant older than 4 months in the absence of breastfeeding.
Two DNA HIV PCR results obtained at least a month apart are negative in an infant older than 6 months.

for more info click this link-

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message



Quick Reply

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Where you live. Leave blank if you don't want to tell.


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
What is the most likely diagnosis? aktorque USMLE Step 1 Forum 12 07-13-2015 02:44 AM
X ray Knee, What's your diagnosis? laithbv USMLE Step 2 CK Forum 7 02-24-2011 12:09 PM
What is your diagnosis? aktorque USMLE Step 1 Forum 12 02-15-2011 11:38 AM
How to confirm the diagnosis? Hohepa USMLE Step 2 CK Forum 5 04-30-2010 06:50 AM
It's about the diagnosis Teodoro88 USMLE Step 2 CS Forum 1 09-28-2009 02:57 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)