Journal Club How to Use and Article About a Diagnostic Test Satyen Gada, MD LT MC (FS) USN NCC Pediatric Residency Program Patients
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How to Use and Article About a Diagnostic Test
Satyen Gada, MD
LT MC (FS) USN
NCC Pediatric Residency Program
Patient 1: 11 yo Caucasian male seen in continuity clinic as a follow up from ER for CC of H. pylori infection. Review of the ER sheet significant for hx of burping with increased frequency and halitosis over the last two days. Family hx of uncle living in California dx with gastritis 6 months ago. He was positive for H. pylori on a blood test. Pt was started on therapy for presumptive H. pylori gastritis. CBC, Stool Guaiac, and H Pylori blood test sent.
Patient 1: In the office, hx from ER is consistent. However, his snxs have completely resolved. All further hx, ROS, PE unremarkable. Lab results neg/wnl. Mother concerned that the test was performed incorrectly or not a good one. According to the internet, her son must have H. pylori, and he did get better on abx.
Patient 1: Your preceptor, a GI specialist, tells you to write the note as she discusses the case with the mother. After some time, the mother storms out angry and upset. Your preceptor shakes his head and throws away two bottles of antibiotics.
Patient 2: The same day in clinic, you evaluate another 11 yo male with abdominal pain. Pt has a two week hx of worsening epigastric pain with occasional emesis. Pt has had a three pound wt loss. States his stool are now black. Increased consumption of milk because it “feels better”. Mother states that he was evaluated in the ER for similar sxns 2 months ago and resolved with four weeks of tx with Zantac. H. pylori blood test at that time was negative. Mother states she also had similar sxns and was diagnosed with an ulcer 1 yr ago and given an antacid which seemed to help.
Patient 2: He is currently not taking any medication.
Vital signs are stable, physical exam significant for epigastric tenderness on deep palpation and stool positive for occult blood.
Your preceptor, a GI specialist, tells you he/she will take care of it and to go ahead and see the triplet NICU f/u’s that have been waiting for 1 hr while you obtained the above detailed hx.
Patient 2: After your NICU f/u, your preceptor tells you despite the negative H pylori blood test, this patient warrants further testing for H pylori with a “breath test” in the GI clinic. You did not appreciate the patient having bad breath, but agree with the plan. When you put the order in AHLTA, you notice there are four available tests for H pylori: blood, urine, stool, and breath test.
Patient 2: The patient returns following the GI appointment with a diagnosis of H pylori peptic ulcer disease, and is being treated with the same regimen that was given to Patient #1 by the ER. The patient returns for a school physical 10 months later and has been sxn free.
1. Both patients had neg H. pylori blood tests. Why was one patient referred to more testing while the other told to discontinue therapy?
2. Why was the breath test ordered for patient #2 over the urine or stool?
3. How do I approach H. pylori testing with future patients?
You return home a bit confused. Looking in the mirror, your reminded of how MOTO you are. You search MD consult to learn more about H. pylori and H. pylori testing and find an article titled….
Comparison of non-invasive tests to detect Helicobacter pylori infection in children and adolescents: Results of a multicenter European study. Megraud et al. Journal of Pediatrics Vol 146:2. Feb 2005.
While you are deleting your junk e-mail that evening, you briefly read your Chief Resident’s messages. One is about some EBM articles on the nccpeds.com website.
You print out the section on how to use an article about a diagnostic test.
food may be the primary reservoir.
Tests are divided into those which require endscopy (invasive) and those which do not (non-invasive).
Treatment: H2 blockers/PPI and:
Amoxicillin/Metronidazole + Clarithromycin x 14d
Eradication rates are 60-80%
Tx failures should be re-treated with Amoxicillin and PPI/H2 blockers + another antibiotic.
Definition of H. pylori status:
Yes: All patients received all tests and they were performed blinded.
Yes: Name of test, company, and method of storage/performance were outlined.
(see Table 1)
+ Age inclusion was broad 2-17. Good exclusion criteria.
+ Good male/female ratio
+ Varied reasons for workup/findings on endoscopy
- Almost exclusively Caucasian.
- Author comments on number of immigrant children in test as well as the fact that all patients warranted endoscopy.
Positive/Negative predictive values depend on prevelance of disease:
Low prevalence will yield more false positives, and therefore lower positive predictive value.
Low prevalence will yield more true negatives, and therefore higher negative predictive value.
Table II . Performances of the diagnostic tests for the 316 patients with gold standard and four tests performed (UBT, HpSA, Urinelisa and Pyloriset EIA-G)
Age group (y)
ROC were created. Authors noted that manufacturer threshold for postive/negative results were not ideal.
Sensitivity for stool could be increased from 72.9 to 80.3 and urine from 63.2 to 72.2 with minimal effect on specificity.
Is the reproducibility high?
YES: Standard criteria for interpretation of biopsies and manufacturer directions for testing were used.
Did comment that degradation of samples in shipment may have occurred when transporting to sites (Germany, Belgium, France).
The choice of tests depends upon issues such as cost, availability, clinical situation, prevalence of infection, pretest probability of infection, and presence of factors (PPI and abx) that may influence test results.