We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
PURITAN MEDICAL

Download Mobile App




Specificity Improved for Urinary Antigen Testing

By LabMedica International staff writers
Posted on 23 May 2017
The cryptococcal antigen lateral flow assay (CrAg LFA) Immy test is standardized for a fast screening point-of-care test for cryptococcosis, detecting cryptococcal antigen in serum and cerebrospinal fluid (CSF).

A delay in laboratory diagnosis is related to sequelae and death and therefore early diagnosis is the key to decrease the high lethality rate due to cryptococcosis. More...
Urine screening would be ideal as a noninvasive approach, but previous studies have shown that fresh urine present false positive results.

Scientists at the National Institute of Infectious Diseases Evandro Chagas performed a prospective cohort study from April 2014 to April 2015 on 77 volunteers: 53 HIV-positive (CD4+ T cell less than 200 cells/mm3) patients, 18 healthy individuals (negative controls), and six HIV-positive patients with active proven cryptococcosis (positive controls). Healthy individuals were included as a negative control and patients presenting proven cryptococcosis as a positive control.

Cryptococcal antigen testing was performed in blood serum and urine from each volunteer using the CrAg LFA Immy test. Each fresh urine sample was tested under two conditions: unheated (untreated) and heated (treated) by five minutes incubation at 100 °C. Clinical specimens such as blood, CSF, and urine were subsequently cultivated to investigate cryptococcal infection. The CrAg LFA in serum samples was considered as the gold standard.

The investigators reported that 24/53 HIV-positive volunteers had a CrAg LFA–positive profile (42.3%) when untreated fresh urine was tested. When heated, only eight samples were positive (15%), presenting 100% of agreement with the positive results obtained from serum samples submitted to CrAg LFA Immy assay. Out of those eight positive patients, five had proven cryptococcosis (positive culture for Cryptococcus neoformans in CSF and/or blood culture) and three patients had cryptococcal antigenemia (negative for Cryptococcus in blood and CSF cultures). The untreated fresh urine has shown 16 false positive results (30.2%). After treatment, those urine samples were negative, as confirmed by negative results in the serum.

The authors concluded that heating of urine prior testing dramatically improved the test’s specificity without compromising the test’s sensitivity. This crucial step has dramatically increased the specificity without compromising test sensitivity, with two additional advantages: no need of enzymatic treatment or sample dilution. The study was published on the journal Public Library of Science Neglected Tropical Diseases.


New
Gold Member
Latex Test
SLE-Latex Test
Serological Pipet Controller
PIPETBOY GENIUS
New
Specimen Radiography System
TrueView 200 Pro
New
Gold Member
Blood Gas Analyzer
Stat Profile pHOx
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








DIASOURCE (A Biovendor Company)

Channels

Molecular Diagnostics

view channel
Image: The new RABTA sets a high standard in laboratory diagnostics (Photo courtesy of Randox)

Pioneering Analyzer with Advanced Biochip Technology Sets New Standard in Lab Diagnostics

A state-of-the-art analyzer combines advanced technology with exceptional efficiency to meet the demanding needs of modern laboratories. Randox Toxicology (Antrim, Ireland) has launched its pioneering... Read more

Hematology

view channel
Image: CitoCBC is the world first cartridge-based CBC to be granted CLIA Waived status by FDA (Photo courtesy of CytoChip)

Disposable Cartridge-Based Test Delivers Rapid and Accurate CBC Results

Complete Blood Count (CBC) is one of the most commonly ordered lab tests, crucial for diagnosing diseases, monitoring therapies, and conducting routine health screenings. However, more than 90% of physician... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.