PracticeVideosBlogFlashcards
All Practice Exams

Free Practice Questions for CSO

Exam-style questions and explanations by OpenExamPrep.

✓ No registration✓ No credit card
147+ Questions
100% Free

Loading practice questions...

Same family resources

Explore More CDR Dietetics Exams

Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.

CDR Registered Dietitian (RD)

Practice Questions200 questionsStudy Guide25 topicsCheat Sheet108 factsFlashcards50 cardsVideos1 videoBlogs2 blogsFree CE

CDR Registered Dietetic Technician (DTR)

Practice Questions264 questionsStudy Guide35 topicsCheat Sheet64 factsFlashcards50 cardsVideos1 videoBlogs1 blogFree CE

CDR CSP Board Certified Specialist in Pediatric Nutrition

Practice Questions150 questionsStudy Guide57 topicsFree CE

CDR CSG Board Certified Specialist in Gerontological Nutrition

Practice Questions100 questionsStudy Guide35 topicsFree CE

CDR CSR Board Certified Specialist in Renal Nutrition

Practice Questions100 questionsStudy Guide54 topicsFree CE

CDR CSOWM Interdisciplinary Specialist Certification in Obesity and Weight Management

Practice Questions100 questionsFree CE

More From This Family

Videos and articles for deeper review.

VideoDTR / NDTR Exam Guide 2026: Current CDR Format & BlueprintArticleFREE CDN Exam Guide 2026: Pass CDR Renal Nutrition Cert26 min readArticleDTR / NDTR Exam Guide 2026: Current CDR Format & Blueprint15 min read
Exam Review

Key Facts: CSO Exam

150

Total Items

125 scored + 25 pretest

3 hrs

Time Limit

CDR

33.6%

Largest Domain Weight

42 of 125 scored items

2,000 hrs

Required Experience

Initial eligibility; approved substitutions allowed

$350

Exam Fee

CDR

5 years

Certification Validity

CDR

The CDR CSO exam has 150 multiple-choice items, including 125 scored and 25 pretest items. Testing is 180 minutes with a 20-minute introductory tutorial. The examination fee is $350. Initial eligibility requires at least two years of current RD/RDN status and 2,000 oncology practice hours in the preceding five years, with approved substitutions. Nutrition Assessment has 42/125 scored items (33.6%). Year-round appointments are offered at Pearson VUE test centres.

Sample CSO Practice Questions

Try these sample questions to review concepts for the CSO exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 147+ question experience with AI tutoring.

1Which of the following BEST describes the Warburg effect in cancer cells?
A.Increased fatty acid oxidation for ATP production
B.Preferential use of aerobic glycolysis even in the presence of oxygen
C.Enhanced ketone body utilization by tumor cells
D.Decreased glucose uptake by malignant tissue
Explanation: The Warburg effect describes the tendency of cancer cells to preferentially metabolize glucose through aerobic glycolysis (producing lactate) even when oxygen is plentiful. This metabolic reprogramming supports rapid biosynthesis of nucleotides, lipids, and amino acids needed for tumor proliferation. It is a hallmark of cancer metabolism.
2A 62-year-old patient with metastatic pancreatic adenocarcinoma has lost 8% of body weight in 4 months and reports loss of appetite and muscle wasting. Per the Fearon 2011 international consensus, this patient meets criteria for:
A.Pre-cachexia
B.Cancer cachexia
C.Refractory cachexia
D.Sarcopenic obesity
Explanation: Per Fearon et al. (2011), cancer cachexia is defined by weight loss greater than 5% over 6 months in absence of simple starvation, OR BMI <20 with any weight loss >2%, OR sarcopenia with weight loss >2%. This patient's 8% loss in 4 months meets the primary criterion. Cachexia is also characterized by anorexia and systemic inflammation.
3Per ESPEN cancer guidelines, the recommended protein intake for an oncology patient with cachexia and adequate renal function is:
A.0.8 g/kg/day
B.1.0 g/kg/day
C.1.2 to 1.5 g/kg/day, up to 2 g/kg/day
D.Greater than 3 g/kg/day
Explanation: ESPEN guidelines recommend protein intake of at least 1.0 g/kg/day, with target of 1.2 to 1.5 g/kg/day for cancer patients, and up to 2 g/kg/day in those with cachexia or systemic inflammation, provided renal function is adequate. Higher protein supports lean body mass preservation in the setting of anabolic resistance.
4A patient receiving radiation therapy to the head and neck reports painful oral ulcers, difficulty swallowing, and decreased intake. Which dietary modification is MOST appropriate for this acute mucositis?
A.Spicy foods to stimulate appetite
B.Soft, moist, bland foods at cool or room temperature
C.Hot, acidic broths to soothe the throat
D.Coarse, high-fiber foods to maintain bowel function
Explanation: For mucositis, soft, moist, bland foods served cool or at room temperature minimize mucosal irritation and pain. Cold or cool textures provide a numbing effect. Avoiding extremes of temperature, acid, spice, and rough textures reduces discomfort and helps maintain intake during treatment.
5Which laboratory finding is MOST suggestive of tumor lysis syndrome (TLS)?
A.Hyponatremia, hypokalemia, hypocalcemia
B.Hyperkalemia, hyperphosphatemia, hyperuricemia, hypocalcemia
C.Hypernatremia, hypercalcemia, hypophosphatemia
D.Hypoglycemia, hypomagnesemia, alkalosis
Explanation: Tumor lysis syndrome occurs when rapid tumor cell breakdown releases intracellular contents into the bloodstream. The classic tetrad is hyperkalemia, hyperphosphatemia, hyperuricemia, and secondary hypocalcemia (calcium binds the released phosphate). TLS is most common in hematologic malignancies (Burkitt lymphoma, ALL) at treatment initiation.
6On the PG-SGA, a patient scores 6 and is categorized as Stage B. The MOST appropriate interpretation is:
A.Well nourished, no nutrition intervention required
B.Moderately malnourished or suspected malnutrition; intervention indicated
C.Severely malnourished; aggressive intervention warranted
D.Score is invalid; reassess in 2 weeks
Explanation: On the Patient-Generated Subjective Global Assessment (PG-SGA), Stage B indicates moderately malnourished or suspected malnutrition, typically with scores of 2 to 8. Stage A is well nourished (0 to 1); Stage C is severely malnourished (9 or greater). A score of 6 in Stage B warrants dietitian intervention and education.
7A patient with pancreatic cancer reports steatorrhea, weight loss, and bloating after meals. The MOST appropriate intervention is:
A.Initiate a low-fat diet (less than 20 g/day)
B.Begin pancreatic enzyme replacement therapy (PERT) with meals and snacks
C.Recommend a high-fiber diet
D.Initiate parenteral nutrition immediately
Explanation: Pancreatic enzyme replacement therapy (PERT) is the standard of care for pancreatic exocrine insufficiency, which causes maldigestion, steatorrhea, and weight loss. Typical dosing starts at 25,000 to 50,000 units of lipase per meal and 10,000 to 25,000 units per snack, taken with the first bite of food.
8Which statement BEST reflects current evidence on the neutropenic diet for adult oncology patients?
A.Strict neutropenic diet significantly reduces infection rates
B.Current evidence does not support strict neutropenic diet; safe food handling practices are recommended
C.All raw fruits and vegetables must be avoided indefinitely after chemotherapy
D.The neutropenic diet should continue for one year after treatment completion
Explanation: Multiple randomized trials and systematic reviews have shown that strict neutropenic diets do not reduce infection rates compared with safe food handling practices. Current ASPEN, AND, and most cancer center guidelines emphasize FDA food safety practices over food restriction in neutropenic patients.
9A patient with head and neck cancer is scheduled for definitive concurrent chemoradiation. Which intervention is associated with the BEST nutritional outcomes?
A.Wait for greater than 10% weight loss before considering enteral access
B.Proactive placement of a prophylactic gastrostomy (G-tube) prior to treatment in high-risk patients
C.Use only oral nutrition supplements regardless of intake
D.Initiate TPN at the start of radiation
Explanation: Prophylactic gastrostomy placement in high-risk head and neck cancer patients (e.g., advanced stage, planned chemoradiation, baseline dysphagia or weight loss) is associated with reduced weight loss, fewer hospitalizations, and improved completion of treatment. Decisions should be individualized but proactive enteral access is preferred for high-risk groups.
10A patient receiving capecitabine should be counseled to avoid which antiviral medication due to a potentially fatal drug interaction?
A.Sorivudine or brivudine
B.Acyclovir at standard doses
C.Oseltamivir
D.Amoxicillin
Explanation: Capecitabine is a fluoropyrimidine prodrug of 5-FU. Coadministration with sorivudine or brivudine inhibits dihydropyrimidine dehydrogenase and can cause fatal 5-FU toxicity. Patients must be screened for recent antiviral use before starting capecitabine. Capecitabine should be taken with food within 30 minutes of a meal.

About the CSO Exam

Specialty certification for Registered Dietitians providing nutrition care to oncology patients across the cancer care continuum. The CSO validates expertise in cancer biology and treatment modalities, validated cancer nutrition assessment (PG-SGA, GLIM, Fearon cachexia), MNT for treatment-related side effects (mucositis, dysgeusia, nausea, diarrhea, GVHD), disease-site-specific protocols (head/neck, pancreatic, gastric, HSCT/BMT, brain), oncologic emergencies, drug-nutrient interactions, supplement and herbal cautions during therapy, and survivorship plus palliative/EOL nutrition.

Exam sponsor: CDR. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Questions

150 questions

Time Limit

180 minutes testing; 20-minute tutorial extra

Passing Score

Angoff-based standard; fixed percent not published

Exam / Certification Fees

$350

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

20.8%

Cancer and Cancer Treatment

Cancer biology, treatment modalities, side-effect profiles (26 of 125 scored items)

33.6%

Nutrition Assessment

PG-SGA, GLIM, Fearon cachexia, ESPEN energy/protein (42 of 125 scored items)

28.0%

Nutrition Interventions

MNT for side effects, disease-site protocols, EN/PN, oncologic emergencies (35 of 125 scored items)

17.6%

Education and Counseling

Motivational interviewing, supplement cautions, survivorship, palliative/EOL (22 of 125 scored items)

Preparing for the CSO Exam

What You Need to Know

  • Passing score: Angoff-based standard; fixed percent not published
  • Exam length: 150 questions
  • Time limit: 180 minutes testing; 20-minute tutorial extra
  • Exam / certification fees: $350 Official sources

Using Our Practice Resources

  • Work through all 147 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

CSO: Suggested Study Strategy

1Use all four official domain counts: 26, 42, 35 and 22 of 125 scored items. Our 50-card allocation is editorial, not an examination simulation.
2Practise PG-SGA numerical triage separately from global categories A/B/C; use GLIM phenotypic and etiologic evidence.
3Use ESPEN estimates of 25–30 kcal/kg/day and protein above 1 up to 1.5 g/kg/day when appropriate; individualise rather than memorising universal prescriptions.
4Practise conditional enteral/PN decisions, refeeding precautions, symptom assessment, monitoring and multidisciplinary referral.
5Check exact anticancer product labels and supplement evidence; distinguish preclinical mechanisms from demonstrated human outcomes.
6Review CDR recertification instructions: the longitudinal pilot is an exception for eligible expiration dates, not the initial certification route.

Frequently Asked Questions

What is the CSO examination format?

150 four-option multiple-choice items: 125 scored and 25 unscored pretest items. Testing lasts 180 minutes; the appointment adds a 20-minute introductory tutorial. CDR offers year-round Pearson VUE test-centre appointments.

Who is eligible for initial CSO certification?

Maintain current CDR RD/RDN status for at least two years from the original RD examination date by the specialty examination date, and document 2,000 hours of oncology nutrition practice as an RD in the preceding five years. Approved substitutions can cover up to 40%, or 800 hours.

What are the official domain weights?

Cancer and Cancer Treatment has 26 of 125 scored items (20.8%); Nutrition Assessment 42 (33.6%); Nutrition Interventions 35 (28%); Education and Counseling 22 (17.6%). Assessment plus Interventions accounts for 61.6%.

What score is needed to pass?

CDR uses an Angoff-based criterion-referenced passing standard and equates examination forms. The handbook does not publish one fixed percentage-correct cutoff. Historical pass rates describe a cohort, not the required score.

What are the fee and retake rules?

The examination fee is $350. An unsuccessful candidate normally waits 60 days and requests CDR reauthorization; the eligibility window is one year. An employer-supported one-time waiting-period waiver can be requested, subject to approval.

Is five-year CSO recertification always examination-only?

No. Examination remains the standard pathway, but the CDR longitudinal-assessment pilot includes eligible CSO credentials expiring January 31, 2029 through June 30, 2030. Pilot requirements include 1,000 specialist practice hours and a $350 fee; check CDR eligibility and enrollment instructions.

How should these clinical cards be used?

Practise assessment and conditional decisions, not automatic treatment recipes. Distinguish PG-SGA scores from global categories; individualise nutrition routes and targets. Review current clinical guidance and the patient’s treatment plan when applying knowledge.