Friday, 27 June 2014

Rapid Urine Test Evaluated for Helicobacter Pylori Infection

A rapid urine test based on enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of anti-Helicobacter Pylori antibodies in urine.

Several methods to diagnose H. pylori infection have been developed, among which the urea breath test (UBT) is currently regarded as the most accurate assay, but the UBT is still expensive and not widely available in many countries.

Scientists at the Ho Chi Minh City Medicine and Pharmacy University (Vietnam) working with Japanese colleagues, enrolled 200 patients undergoing upper gastrointestinal endoscopy from October 2012 to December 2012. Three biopsies were taken from each patient: two for histologic examination and one for the rapid urease test (RUT).

The biopsy for RUT was taken from the greater curvature of the corpus, about 2 cm above the atrophic border. This biopsy location has been reported to optimize the sensitivity of the PyloriTek RUT to detect H. pylori (Serim Research Co.; Elkhart, IN, USA). Urine samples were collected and were processed within one hour of collection for the detection of antibodies against H. pylori using the Rapirun Helicobacter pylori Antibody Stick (Otsuka Pharmaceutical Co., Ltd.; Tokyo, Japan). The test measures human immunoglobulin G (IgG) antibodies against H. pylori in urine using the principle of immunochromatography.

Of the 200 patients, 111 (55.5%) were diagnosed as being H. pylori positive. The sensitivity, specificity, and accuracy of the Rapirun Stick test were 84.7%, 89.9%, and 87.0%, respectively. There were 17 (8.5%) false-negative patients and 9 (4.5%) false-positive patients. Of the 24 patients with gastro-duodenal ulcer, 22 (91.7%) had H. pylori infection. However, 7 of 22 (31.8%) patients with reflux esophagitis also had the infection.

The authors demonstrated the usefulness of the Rapirun Stick test for the diagnosis of H. pylori infection in a Vietnamese population and the sensitivity, specificity, and accuracy of the Rapirun Stick test were high. In several patients, RUT and histologic examination produced false-negative or false-positive results, leading to the possible misdiagnosis of H. pylori infection. The study was published on May 7, 2014, in the World Journal of Gastroenterology.

Lab Medica)

Sunday, 22 June 2014

MERS-CoV Immunity Not Widespread

A study has found no significant rates of antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV) in one Middle East-North Africa (MENA) region, suggesting that the virus has not been circulating in humans for long, and that the majority of the population remains susceptible to infection. The results of the study by Aburizaiza et al., was published in the January 2014 issue of the Journal of Infectious Diseases, (Vol. 20 (2)).

The study involved 130 blood donors and 226 slaughterhouse workers from Jeddah and Makkah (Saudi Arabia) sampled during 2012. Serum samples were analyzed using the recommended staged serological approach: screening of IgG and IgM antibodies by conventional IFA based on MERS-CoV-infected and non-infected cells (EUROIMMUN AG; L├╝beck, Germany), followed up by confirmation by discriminative recombinant IFA based on viral spike proteins and plaque-reduction neutralization assay. Only eight sera were positive in the screening test, and these reactions were subsequently resolved to be specific for established coronaviruses. These results highlight the importance of multistage serological testing. Nevertheless, the level of cross reactivity with other human coronaviruses in the screening test is relatively low. Significantly, these results demonstrate an absence of population immunity in the region and at the sampling timepoint.

MERS-CoV is an emerging pathogen which is responsible for an outbreak of severe acute respiratory illness predominantly in the Arabian Peninsula with a high number of fatalities. From September 2012 to March 2014, there have been 206 laboratory-confirmed cases with 86 deaths. The transmission mechanisms of the virus remain unknown, and animal reservoirs are suspected to play a role. In a further serological study, antibodies against MERS-CoV were detected in a majority of dromedary camels sampled in the United Arab Emirates in 2003 and 2013 (Meyer et al., Emerging Infectious Diseases, Vol. 20 (4), April 2014). The high antibody prevalence suggests a potential role for camelids in the emergence and spread of the virus in humans. 

(Credits: Lab Medica)

Tuesday, 3 June 2014

When to worry about blood test results? Abnormal readings aren’t always a problem !

Blood tests are an indispensable tool of medicine. They’re used to screen, diagnose, confirm, and monitor diseases. There are many hundreds of them, and each one is subject not only to observation but also to interpretation.

There is no such thing as a perfect lab test, but all tests done by accredited labs today use methods that have been scrutinized and approved by National Accreditation Board for Testing and Calibration Laboratories (NABL). And the government certifies and inspects these labs regularly to make sure they’re keeping up standards.

Those “reference ranges” you see on the reports may vary slightly from lab to lab, depending on which of several possible methods a lab chooses to use. Test results can also fall outside the reference range for reasons that have nothing to do with disease or medications.

One common example: ­Patients who follow the usual instruction to have “nothing to eat or drink the night before” can end up with high blood urea nitrogen, which assesses kidney function. Their kidneys are fine, but they’ve dehydrated themselves enough to cause an elevated reading. That’s why we tell our patients to have “nothing to eat or drink from dinner the night before—except for liberal amounts of water.” As a bonus, adequate hydration makes it easier to draw blood by plumping up the veins.

And triglycerides and blood glucose levels, included in many routine blood tests, are very sensitive to the time of the last meal and reach the “fasting” baseline only after 8 to 12 hours without eating. So patients who had that late-night snack and have their blood drawn early the next morning might have out-of-range ­results.

Other abnormal readings may or may not indicate a problem. A high lev­el of creatine phosphokinase, a muscle enzyme, can signal a heart or muscular ailment—or it can mean you worked out shortly before your blood was drawn.

And if you’re an adolescent or recovering from a broken bone, a high level of alkaline phosphatase, a bone (and liver) enzyme, is completely expected; but if you’re not, it could be an ominous sign of liver disease or certain cancers.

So even if you exercise your option to receive your results directly from the lab, you should still get your doctor to weigh in and not try to decode the data yourself.