HS200 Unit 8 Kidney Stone Diagnostic Test Rationale Example

Reviewed by Elspeth Marlowe, MSN, RN Diseases of the Human Body Purdue University Global Free custom sample in 24 to 48h

In this HS200 Unit 8 diagnostic test rationale, a composite 41-year-old with sudden waves of left flank pain spreading to the groin is suspected of having a kidney stone in the ureter, and three tests are justified by the question each answers. Purdue Global HS 200 asks BS in Health Science learners to state a test's question before its result. A urinalysis asks whether there is blood or infection in the urine. A serum creatinine asks whether kidney function is affected. Imaging asks where the stone is and whether the kidney is swollen, and the paper weighs ultrasound against noncontrast CT using a randomized trial. A closing section explains how results would change management, from passing the stone to urgent relief of an infected blockage.

CourseHS200 Diseases of the Human Body
UnitUnit 8
Paper typeDiagnostic test rationale
LengthAbout 540 words, 4 pages double-spaced
FormatAPA 7 student paper
SchoolPurdue University Global
ProgramBS in Health Science
UpdatedOctober 2026

Free sample paper for HS200 Unit 8

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The Question Before the Test: A Unit 8 Diagnostic Test Rationale for Sudden Flank Pain and Blood in the Urine

[Student Name]

Purdue University Global

HS200: Diseases of the Human Body

Unit 8 Diagnostic Test Rationale

[Instructor Name]

[Date]

The patient is composite; the trial, review and textbook cited are real, and reference ranges are left to the laboratory.

What this part is doingPutting the test-question rule in the lead tells the reader every test will be justified by its question first.
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The Case

A composite 41-year-old man wakes with severe, cramping pain in his left side below the ribs that comes in waves and spreads toward his groin. He cannot find a comfortable position and has vomited twice. He has no fever. He had a similar but milder episode two years ago. The suspected process is a kidney stone that has moved into the ureter, the tube from the kidney to the bladder, causing a blockage. The ureter's muscle contracts against the stone, producing waves of pain, and the blockage stretches the kidney's collecting system (Khan et al., 2016).

Test 1: Urinalysis

Question it answers: Is there blood in the urine, and is there evidence of infection? What it would reveal: A stone scraping the lining of the urinary tract usually causes microscopic blood in the urine, which supports the suspected process. White blood cells, bacteria or nitrites would suggest infection behind the blockage, an emergency because infected urine trapped behind a stone can spread to the blood. What a normal result would mean: The absence of blood makes a stone less likely but does not rule it out, since some stones cause no bleeding.

Test 2: Kidney Function (Serum Creatinine)

Question it answers: Is the blockage affecting kidney function? What it would reveal: A rise in creatinine, a waste product the kidneys clear, suggests that kidney function is reduced. With one kidney blocked, the other usually compensates, so a large rise would raise concern about a problem in both kidneys or a person with only one working kidney.

Each test is chosen to answer a different question: the urine asks what is happening inside the tract, the blood asks whether the kidneys are coping and the image asks where the stone is.

What this part is doingMapping each test to a distinct question shows the rationale avoids ordering tests that duplicate each other.
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Test 3: Imaging

Question it answers: Is there a stone, where is it, how large is it and is the kidney swollen from blockage? Options: A noncontrast computed tomography scan shows almost all stones and their exact size and position. An ultrasound shows swelling of the kidney from blockage and some stones, without radiation. In a large randomized trial of patients with suspected kidney stones in emergency departments, starting with ultrasound led to lower radiation exposure without a significant difference in serious complications or high-risk missed diagnoses compared with starting with CT (Smith-Bindman et al., 2014). Reasoning for this patient: Because he has had a stone before and has no fever, an ultrasound first is reasonable, with CT if the result is unclear or the pain does not settle.

What this part is doingTailoring the imaging choice to this patient's history shows the rationale applies evidence rather than reciting a standard order.
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How the Results Would Change Management

A small stone with no infection and normal kidney function may be allowed to pass with pain control and fluids. Signs of infection, a large stone or reduced kidney function would prompt urgent consultation to relieve the blockage. Later, stone analysis and urine tests can identify the cause to prevent recurrence (Rogers, 2023).

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References

Khan, S. R., Pearle, M. S., Robertson, W. G., Gambaro, G., Canales, B. K., Doizi, S., Traxer, O., & Tiselius, H.-G. (2016). Kidney stones. Nature Reviews Disease Primers, 2, 16008. https://doi.org/10.1038/nrdp.2016.8

Rogers, J. L. (Ed.). (2023). McCance & Huether's pathophysiology: The biologic basis for disease in adults and children (9th ed.). Elsevier.

Smith-Bindman, R., Aubin, C., Bailitz, J., Bengiamin, R. N., Camargo, C. A., Corbo, J., Dean, A. J., Goldstein, R. B., Griffey, R. T., Jay, G. D., Kang, T. L., Kriesel, D. R., Ma, O. J., Mallin, M., Manson, W., Melnikow, J., Miglioretti, D. L., Miller, S. K., Mills, L. D., ... Cummings, S. R. (2014). Ultrasonography versus computed tomography for suspected nephrolithiasis. New England Journal of Medicine, 371(12), 1100-1110. https://doi.org/10.1056/NEJMoa1404446

The Purdue Global HS200 Unit 8 instructions

The eighth unit usually asks students to justify a set of diagnostic tests for a case, explaining what each would reveal and why it is needed, often before any results are given. The paper is usually short, and instructors look for a clear question attached to each test, an explanation of what positive and normal results would mean and an argument for the order or choice among options. Reference ranges, where the course supplies them, should be used with units. Discussing a test that may come back normal can be useful if it rules out a rival process. Evidence comparing test options, cited with year, strengthens the rationale.

How this HS200 Unit 8 example is built

The rationale presents the case and the suspected mechanism of a stone obstructing the ureter. The urinalysis section states its question, what blood or signs of infection would mean and what a normal result would and would not exclude. The creatinine section explains why one blocked kidney may not raise it. The highlighted sentence summarizes the three questions. The imaging section compares CT and ultrasound with trial evidence and chooses ultrasound first for this patient. A final section explains how combinations of results would lead to watchful waiting or urgent treatment and later prevention. Each test section ends with a line on what a normal result would and would not exclude.

HS200 Unit 8 rubric: what earns full points

Test rationales are generally graded on the clarity of each test's question, accuracy of what results would show, reasoning about choice and order, use of evidence and relevance to the case. The question attached to each test often carries the most weight, since the unit is built on it. Accuracy rewards correct interpretation of positive and normal results. Reasoning earns credit when the student explains why one option is chosen over another for this patient. Evidence from trials or guidelines, cited with year, supports those choices. Avoiding unnecessary tests and linking results to management complete the score. Rationales that explain why a test is not needed, as well as why others are, often stand out.

HS200 Unit 8 help from the desk

A frequent weakness is a list of tests with descriptions copied from a lab manual and no question attached to each. Another is covering abnormal results but staying silent on what a normal one would rule out. Some students order every possible test, which suggests no reasoning about need. Others choose imaging without weighing radiation or the patient's history. Leaving out how results would change care makes the rationale feel unfinished. If your case involves a different complaint, perhaps shortness of breath or a new rash with fever, send the case details, and we will justify each test by the question it answers. Overlooking the link between results and next steps leaves the reader unsure why the tests matter.

Get an HS200 Unit 8 example written to your instructions

Everything needed is the Unit 8 scenario plus its instructions and rubric. Each test that case calls for is explained, in blocks or in narrative as the prompt specifies, and the rationale reaches you in 24-48h. The first custom sample is free, and its patient exists only on the page. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.

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HS200 Unit 8 questions, answered

How many tests should a rationale cover?

As many as the prompt asks for, often two or three. Covering fewer tests in depth usually beats listing many, since each one needs its question, its mechanism and its expected result. If the case clearly calls for a test the prompt does not mention, a sentence noting it can show judgment without expanding the paper beyond its limits.

Should the rationale include actual reference ranges?

If the case or the course text supplies them, yes, with units. Ranges differ between laboratories, so quoting one from an unrelated website can contradict the values your instructor expects. Where no range is given, describing the expected direction and the reason for it, elevated because damaged cells release the protein, often satisfies the requirement.

Is it acceptable to discuss a test that would be normal?

Often it helps. A normal result can rule out a rival process, which is part of reasoning about diagnosis. Say what the normal result would exclude and what it would leave open. Graders tend to credit a rationale that treats tests as answers to specific questions rather than as confirmations to be collected.

Where can I find a free HS200 Unit 8 sample paper?

The complete Unit 8 diagnostic test rationale is posted here, justifying urinalysis, creatinine and imaging for a suspected kidney stone.

Should a suspected kidney stone always get a CT scan?

Not always. A trial found starting with ultrasound lowered radiation without more serious complications, with CT used when ultrasound is unclear.