Week 1 Discussion 2. Reply to each students discussion post 2-3 paragraphs

Respond to at least two of your fellow students discussion posts. These responses must include a journal, news, or website article that critically reflects and pertains to the points of the initial post. You can either agree, disagree, or elaborate using these sources.

Richard Williams (students name)

Sensitivity and Specificity

Disease

The disease of interest is a sexually transmitted infection [STI]. Precisely, syphilis, a disease caused by the bacterium treponema pallidum, is associated with life-threatening complications if left untreated (Spicknall et al., 2021). Studies show that syphilis was at 2.1 cases per 100,000 populations in 2001, and the rates have increased five folds to 11.9 cases per 100 0000 populations (Amerson et al., 2022). The infection patterns differ across racial groups and gender, with men at higher risk and transgender groups. Thus, the United States Preventive Services Task Force [USPSTF] recommends regular screening for at-risk persons.

Screening Test

Regarding screening tests, the Dual Path Platform [DPP] Syphilis Screen & Confirm is a point-of-care test [POP] that simultaneously detects and confirms syphilis infection. The product performance has a sensitivity of 96.5% (treponemal) and 97.7% ( non treponemal) and the specificity of 95.5% treponemal and 98.6% non treponemal (Chembio Diagnostics, Inc, 2023).

Predictive Positive Value [PVV] and the Predictive Negative Value [PNV]

Sensitivity

True positive results = [0.000119 * 0.965 * 100,000]= 11.48

Specificity

True negative results = [(1 – 0.000119) * 0.955* 100,000]= 108638.945

False positive
 =108638.945 *(1 – 0.955) = 4,477.79

False negative=1.9 * (1 – 0.965) = 0.4175

PVV= [11.48]/ [11.48+4,477.79] =0.00256

PNV=[108638.945]/[108638.945+0.4175]=0.999996

Making sense of DPP as a screening tool

The natural history of syphilis is depicted by infections that occur in stages and with the risk of relapse even after treatment. Studies show that 23.65% of patients experienced secondary relapse five years after discharge. At the same time, benign syphilis occurred early after the first years of discharge, while cardiovascular syphilis did not recur in patients diagnosed after the age of 15 years (Clark & Danbolt, 1955). Meanwhile, if left untreated, the disease’s progression negatively impacts patient outcomes. For this reason, screening is recommended for patients at high risk of infection, and the test should be routine (Amerson et al., 2022). The syphilis test costs $213 per person, while confirmed and treated cases cost $ 5517 per case (Williams & Berruti, 2021). Based on the aforementioned factors, the PNV and PVV value for DPP shows that the positive test results are more likely to be false. Thus, considering the risk of relapse, the increasing prevalence rates of syphilis and the cost factors, DPP would not be a suitable screening tool for syphilis since using the DPP tool for regular screening will only increase the cost.
 

 

References

Amerson, E. H., Castillo Valladares, H. B., & Leslie, K. S. (2022). Resurgence of Syphilis in the US—USPSTF Reaffirms Screening Guidelines. 
JAMA Dermatology, 
158(11), 1241. https://doi.org/10.1001/jamadermatol.2022.3499

Chembio Diagnostics, Inc. (2023). 
DPP® syphilis screen & confirm europe – chembio diagnostics, inc. https://chembio.com/products/dpp-syphilis-screen-confirm-europe/

Clark, E. Gurney., & Danbolt, N. (1955). The Oslo study of the natural history of untreated syphilis. 
Journal of Chronic Diseases, 
2(3), 311–344. https://doi.org/10.1016/0021-9681(55)90139-9

Williams, A. M., & Berruti, A. A. (2021). Costs of identifying cases of syphilis using rapid syphilis tests in multiple nonclinical settings in the United States. 
Sexually Transmitted Diseases, 
48(11), 895–899. https://doi.org/10.1097/olq.0000000000001464

less

Drew Isais (student’s name)

Select a Disease:

            
Infectious Mononucleosis (IM)

Find the prevalence of that disease in the US:

            
500 per 100,000 (Williams-Harmon et al. 2016)

Find a screening test for that disease and the manufacturer’s reported sensitivity and specificity:

            
MonoSpot Test: Sensitivity = 90%, Specificity = 95% (Stuempfig & Seroy. 2022)

Apply that proportion to a random population of 100,000 people:

            
Disease prevalence already cited per 100,000 people.

Calculate the predictive positive value and the predictive negative value:

· Predictive Positive Value: TP/TP+FP

                        
(90/90+10) = 0.9

· Predictive Negative Value: TN/TN+FN

                         (95/95+5) = 0.95

Step 1:

	Disease (+)	Disease (-)
Test (+)	90%	10%
Test (-)	5%	95%
Total	500	99,500

Step 2:

	Disease (+)	Disease (-)
Test (+)	450	4,975
Test (-)	50	94,525
Total	500	99,500

Infectious Mononucleosis, also known as “Mono”, is of viral etiology with a primary transmission of saliva. 90% of cases are caused by the Epstein-Barr Virus (EBV) and cause a myriad of systemic symptoms such as: fever, malaise, fatigue, chills, and lymphadenopathy of the anterior cervical and supraclavicular lymph nodes with the most notable symptom of a sore throat. Additional diagnostic considerations include splenomegaly (enlarged spleen) which can increase the chances of splenic rupture with loaded weight bearing activities, high impact movements, or trauma (Thorley-Lawson. 2001). Infected individuals can range from asymptomatic to mild and even severe symptoms lasting up to six months (Crawford. 2001). High risk populations have regularly included teenagers, and young adults from the ages of 15-19 who belong to more densely populated communities like college universities and the military (Evans. 1960).

The incidence of IM in the United States is about 200-800 cases per 100,000 and averages at 500 cases per 100,000 (Luzuriaga & Sullivan. 2010). The annual incidence rate over the course of 30 years has been shown to be as high as 11 to 48 cases per 1,000 people in populations that live and work within close proximity to one another (Candy et al. 2002). IM is not considered a severe illness due to its relatively mild symptoms; however, due to its mode of transmission, ease of susceptibility of contraction, and ability to affect the daily activities of a person who contacts it, MonoSpot testing has been shown to be a valid, accurate and inexpensive test to rule in or rule out pathology in the acute setting (Wang & Hwang. 2022).

The MonoSpot test is a simple and effective blood test used to assess immunoglobulins, IgM and IgG. If these heterophile specific antibodies are discovered they can be routinely used for the diagnosis of IM. IgM and IgG antibodies have a high sensitivity and specificity for the diagnosis with 97% and 94% respectively (Bruu et al. 2000). EBV testing can be further investigated with a hematologic test used to identify lymphocytosis, a common association with IM. Diagnosis can be made with an absolute count of >4500/mL without differential or >50% with differential on a peripheral smear. The average white blood cell (WBC) count in IM positive average 12,000 to 18,000/mL (Auwaerter. 1999).

Due to its availability and accessibility for populations such as university students or active duty military, monospot screening tests should be performed on symptomatic personnel exhibiting general symptoms accompanied with a sore throat. By doing so, patients can be informed of their diagnosis and preventative measures to prevent disease spread in addition to “red flag” criteria such as splenomegaly.

References

Auwaerter P. G. (1999). Infectious mononucleosis in middle age. 
JAMA, 
281(5), 454–459. 

https://doi.org/10.1001/jama.281.5.454

Bruu, A. L., Hjetland, R., Holter, E., Mortensen, L., Natås, O., Petterson, W., Skar, A. G., Skarpaas, T., Tjade, T., & Asjø, B. (2000). Evaluation of 12 commercial tests for detection of Epstein-Barr virus-specific and heterophile antibodies. 
Clinical and diagnostic laboratory immunology, 
7(3), 451–456. https://doi.org/10.1128/CDLI.7.3.451-456.2000

Candy, B., Chalder, T., Cleare, A. J., Wessely, S., White, P. D., & Hotopf, M. (2002). Recovery from infectious mononucleosis: a case for more than symptomatic therapy? A systematic review. 
The British journal of general practice : the journal of the Royal College of General Practitioners, 
52(483), 844–851.

Crawford D. H. (2001). Biology and disease associations of Epstein-Barr virus. 
Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 
356(1408), 461–473. 

https://doi.org/10.1098/rstb.2000.0783

Evans A. S. (1960). Infectious mononucleosis in University of Wisconsin students. Report of a five-year investigation. 
American journal of hygiene, 
71, 342–362. 

https://doi.org/10.1093/oxfordjournals.aje.a120118

Luzuriaga, K., & Sullivan, J. L. (2010). Infectious mononucleosis. 
The New England journal of medicine, 
362(21), 1993–2000. https://doi.org/10.1056/NEJMcp1001116

Stuempfig ND, Seroy J. Monospot Test. [2022]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: 

https://www.ncbi.nlm.nih.gov/books/NBK539739/

Thorley-Lawson D. A. (2001). Epstein-Barr virus: exploiting the immune system. 
Nature reviews. Immunology, 
1(1), 75–82. 

https://doi.org/10.1038/35095584

Wang, E. X., Kussman, A., & Hwang, C. E. (2022). Use of Monospot Testing in the Diagnosis of Infectious Mononucleosis in the Collegiate Student-Athlete Population. 
Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine, 
32(5), 467–470. https://doi.org/10.1097/JSM.0000000000000996

Williams-Harmon, Y. J., Jason, L. A., & Katz, B. Z. (2016). Incidence of Infectious Mononucleosis in Universities and U.S. Military Settings. 
Journal of diagnostic techniques and biomedical analysis, 
5(1), 10.4172/2469-5653.1000113. 

https://doi.org/10.4172/2469-5653.1000113