Diagnosis Webinar Pre-Test Question Title * 1. A 15 year old white female presents with persistent cough and recurrent sinusitis. An oropharyngeal culture demonstrates the presence of Pseudomonas aeruginosa. Which of the following statements is correct? A. The patient is unlikely to have CF because it would have been detected by newborn screening B. The presence of Pseudomonas aeruginosa is unusual in a teenager and further workup should include an evaluation for CF C. The patient meets diagnostic criteria for CF D. A sweat test would be next best test to help diagnose CF for this patient E. Both B and D are correct answers for this question Question Title * 2. In the 15 year old female described above, the results of the sweat chloride are 51 and 54 mmol/L. Which of the following statements best describes the correct interpretation of this result? A. The patient does not have CF because the sweat chloride values are normal for this age group B. The sweat chloride values are abnormal but are not diagnostic of CF C. The patient meets the diagnostic criteria for CF D. CFTR mutation assessment with an expanded genetic analysis would be appropriate in this patient E. Both B and D are correct answers for this question Question Title * 3. A 2 week old infant has a positive CF newborn screening test showing one copy of F508del mutation and one copy of G551D mutation. Sweat chloride values of 42 and 39 mmol/L are obtained using bilateral sampling of adequate volumes. It is most likely that this infant: A. Has cystic fibrosis B. Has CFTR related metabolic syndrome C. Was subject to a laboratory error in analysis of chloride D. Was subject to an error in blood spot collection in the newborn nursery Question Title * 4. A newborn girl at age 3 weeks had a positive CF newborn screening test. Her mother was found to carry a disease-causing CFTR mutation and her father was found to have CFTR variant of unknown significance. Amniocentesis revealed that the infant has both the mutation and the variant. Her sweat chloride values are 9 and 10 mmol/L. Appropriate management of this infant includes: A. Begin pancreatic enzyme and salt supplements while further diagnostic evaluation is undertaken B. Discharge the infant from follow-up at the CF Center C. Communicate the findings to the primary care physician and schedule the infant for a repeat sweat test. D. Presumptively follow all guidelines for care of CF infants until more literature is published on the variant of unknown significance. Question Title * 5. The infant in the prior scenario had a repeat sweat chloride of 31 mmol/L at two months of age. She is next seen for a follow-up visit at the CF clinic at one year of age and is noted to have excellent growth and no respiratory illnesses or symptoms. She has a pharyngeal culture performed which grows Pseudomonas aeruginosa. The best immediate management of this child includes: A. Begin therapy targeted against Pseudomonas aeruginosa and confirm the CF diagnosis B. Do not treat the Pseudomonas. aeruginosa, because the child does not have CF C. Begin therapy targeted against Pseudomonas aeruginosa and consider further evaluation for a possible diagnosis of CF D. Perform nasal potential difference measurement before deciding whether to treat the child for Pseudomonas aeruginosa infection. Question Title * 6. A 4 week old infant is referred to the CF Center because of a positive NBS. Mutation analysis using a panel of 23 CFTR mutations from his CF NBS test showed 1 copy of F508del on one allele and no identified mutations on the other allele. He undergoes sweat testing, and his sweat chloride concentrations were 31and 35 mmol/L. Of the following, which tentative conclusion and course of action are best? A. He is a CF carrier because his sweat chloride concentration is normal, but a repeat sweat test is needed B. He probably has CF, so the parents should be informed of this diagnosis and CFTR expanded genetic analysis done C. He likely has CRMS, which should be explained to the parents, and another sweat test ordered at 6 months of age D. There is no basis for even a tentative diagnosis, so a sweat test should be repeated within 2 months Question Title * 7. In the case of the 4 week old infant described above with positive NBS and one F508del mutation, CF treatment should be initiated while efforts to establish a diagnosis of CF are pursued further. A. True B. False Question Title * 8. A 4 week old infant is referred to the CF Center because of an initially high IRT level that is confirmed with repeat testing at 2 weeks of age in a state that uses the IRT/IRT protocol. He then undergoes bilateral sweat testing, and his sweat chloride concentrations are 31 and 35 mmol/L. Which one of the following statements is true? A. These sweat chloride values are higher than the normal range B. Chloride levels of 31 and 35 mmol/L are consistent with a diagnosis of CF C. The most helpful additional test in such a case is CFTR analysis D. Chloride levels of 31 and 35 mmol/L are not compatible with a diagnosis of CF E. Both A and C are correct answers for this question Question Title * 9. A 4 week-old infant with an ultrahigh IRT level (>300 ng/ml) has one F508del mutation and the 23 CFTR mutation testing was otherwise negative, i.e., a single CF-causing allele was detected. What is your interpretation? A. The baby is probably a CF heterozygote carrier B. The baby may be a CF compound heterozygote C. CFTR expanded genetic analysis may identify another point mutation D. Sweat chloride testing should be the first step in testing for this infant E. All of the above could be for this infant Question Title * 10. When performing bilateral QPIT with the Gibson-Cooke method on a 3 week-old baby, resulting in 65 mg from the left arm and 75 mg from the right arm, and chloride values considered reliable by your clinical lab, which of the following procedures is correct? A. The lab should report the results of chloride analyses from each sweat sample B. The lab should combine the two sweat samples to avoid a QNS result C. The lab should combine the two sweat samples to ensure a reliable chloride analysis D. The lab should only report the chloride level from the right arm sweat sample E. The lab should repeat the sweat test Question Title * 11. Which of the following statements are most likely to be the etiology of a 20 mmol/L false negative sweat chloride result in a full term 3 week-old infant with a high IRT level and two CF-causing CFTR mutations? A. Hypoproteinemic edema B. Lab error in chloride analysis C. Baby is dehydrated D. Age of the patient E. A and B Question Title * 12. An adolescent 15 y/o female diagnosed with asthma since 5 years of age develops recurrent pancreatitis, shows a sweat chloride of 49 mmol/L, and a genotype of F508del/no mutation found in a DNA analysis of 23 CFTR mutations. You are concerned that she has CF. What is the next best step or steps for evaluation? A. Obtain a stool for fecal elastase B. The patient needs CFTR sequencing and an assessment for deletions or duplications C. Send blood for amylase and lipase D. A chest radiograph should be ordered E. All of the above are correct Question Title * 13. Causes of a false positive sweat test include all but one of the following. A. Evaporation of liquid during sweat collection, transport to the lab, and/or transfer within the lab B. Improper dilutions C. Use of the Macroduct method D. Hypothyroidism E. Protein-energy malnutrition Done
