100+ Free RDN-AP Practice Questions

Pass your Advanced Practitioner Certification in Clinical Nutrition (RD-AP / RDN-AP) exam on the first try — instant access, no signup required.

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Per ASPEN, the recommended PN macronutrient strategy in a stable adult on home PN includes:

100% calories from dextrose

Balanced macronutrients with dextrose 50-60% (less than 4-7 mg/kg/min infusion), amino acids 1.0-2.0 g/kg, lipids 1.0 g/kg (less than 1 g/kg/day soybean-only), and cycling typically over 12-16 hours

Amino acids only with no dextrose

Lipids 3 g/kg with no dextrose

to track

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2026 Statistics

Key Facts: RDN-AP Exam

150

Total Items

125 scored + 25 pretest

44%

Largest Domain Weight

Nutrition Assessment & Diagnosis

2x/yr

Testing Windows

NOT year-round

2,000 hrs

Required Post-RD Hours

Within past 5 years

Adv. Practice

Demonstrated Via

Grad degree / research / publication / specialty cert

5 years

Certification Validity

CDR

The RDN-AP (Advanced Practitioner Certification in Clinical Nutrition) is administered by CDR for senior clinical RDNs. The exam consists of 150 multiple-choice items (125 scored + 25 pretest) over 3 hours. Two testing windows per year (NOT year-round). Eligibility requires an active RD/RDN credential plus 2,000 hours of post-RD clinical nutrition practice within the past 5 years AND one demonstration of advanced practice (graduate degree, research presentation, peer-reviewed publication, or clinical specialist certification). Nutrition Assessment and Diagnosis is the largest domain at 44%.

Sample RDN-AP Practice Questions

Try these sample questions to test your RDN-AP exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1An advanced practitioner is performing a nutrition-focused physical exam (NFPE) on a 72-year-old man hospitalized for COPD exacerbation. The clinician notes hollowing at the temples, prominent clavicles, and visible scapular wasting. Which combination of findings BEST supports a diagnosis of severe muscle wasting per AND/ASPEN malnutrition criteria?

A.Temporal wasting plus clavicle prominence plus scapular wasting in the context of chronic illness

B.BMI of 22 with stable weight over six months

C.Pitting edema of the lower extremities only

D.Loss of subcutaneous fat at the orbits without muscle changes

Explanation: AND/ASPEN 2012 consensus criteria use NFPE findings of muscle wasting (temples, clavicles, scapula, deltoid, quadriceps, gastrocnemius) together with clinical context (acute illness/injury, chronic illness, or social/environmental circumstances) to diagnose malnutrition. Severe muscle wasting in multiple sites under chronic illness supports severe chronic-disease-related malnutrition. BMI alone, isolated edema, or fat loss without muscle changes are insufficient.

2Which combination of phenotypic and etiologic criteria, per the GLIM framework, is REQUIRED to diagnose malnutrition?

A.Two phenotypic criteria with no etiologic criteria

B.At least one phenotypic criterion AND at least one etiologic criterion

C.Three etiologic criteria with no phenotypic criteria

D.Any one phenotypic OR one etiologic criterion alone

Explanation: GLIM (Global Leadership Initiative on Malnutrition) requires at least one phenotypic criterion (non-volitional weight loss, low BMI, or reduced muscle mass) AND at least one etiologic criterion (reduced food intake/assimilation or disease burden/inflammation) after a positive screen. Severity (moderate vs severe) is then graded on phenotypic criteria.

3An advanced practitioner is asked to interpret a DXA body composition scan in a 68-year-old woman with cirrhosis and ascites. Which limitation MOST affects the validity of fat-free mass estimates in this patient?

A.DXA underestimates bone mineral content in elderly women

B.Ascites and tissue overhydration cause DXA to overestimate lean soft tissue

C.DXA cannot measure trunk fat in obese patients

D.DXA radiation exposure exceeds clinical thresholds

Explanation: DXA assigns water in soft tissue to the lean compartment because it cannot distinguish water from protein. In patients with ascites, edema, or fluid overload, lean soft tissue mass is overestimated, falsely reassuring clinicians about muscle mass. ESPEN and EASL guidance recommend interpreting body composition cautiously in cirrhosis and pairing imaging with NFPE. BIA shares the same hydration confounding.

4On NFPE, a malnourished alcohol-use-disorder patient has angular cheilitis, magenta tongue, and seborrheic dermatitis around the nasolabial folds. These findings MOST strongly suggest deficiency of which micronutrient?

A.Vitamin A

B.Riboflavin (B2)

C.Vitamin C

D.Iron

Explanation: Angular cheilitis (cracking at the corners of the mouth), magenta/glossitis tongue, and seborrheic dermatitis in the nasolabial area are classic riboflavin (B2) deficiency findings, although B6 and niacin can produce overlapping signs. Vitamin A causes bitot's spots/xerophthalmia, vitamin C causes perifollicular hemorrhage and corkscrew hairs, and iron causes koilonychia and pallor.

5Which screening tool is BEST validated for nutrition risk in adult hospitalized patients and is recommended by ESPEN for routine inpatient screening?

A.MUST (Malnutrition Universal Screening Tool)

B.MNA-SF (Mini Nutritional Assessment-Short Form)

C.NRS-2002 (Nutrition Risk Screening 2002)

D.STAMP (Screening Tool for the Assessment of Malnutrition in Pediatrics)

Explanation: ESPEN recommends NRS-2002 for adult inpatients because it incorporates both nutritional status and disease severity, validated specifically against clinical outcomes in hospital populations. MUST is more often used in community/outpatient settings, MNA-SF is for older adults, and STAMP is pediatric.

6An advanced practitioner is reviewing a 56-year-old patient with sepsis on day 4 of ICU admission. Albumin is 1.9 g/dL, prealbumin is 8 mg/dL, and CRP is 220 mg/L. The clinician should interpret these values as PRIMARILY reflecting:

A.Severe protein-energy malnutrition requiring immediate aggressive feeding

B.The acute-phase inflammatory response, not nutritional status

C.Volume depletion with hemoconcentration

D.Hepatic synthetic failure from drug toxicity

Explanation: Albumin and prealbumin are negative acute-phase reactants; their levels fall during inflammation regardless of nutritional intake. With CRP at 220 mg/L, low albumin/prealbumin reflects severe inflammation, not malnutrition. ASPEN and AND no longer endorse using serum proteins as nutrition status markers; assessment should rely on weight history, intake, NFPE, and functional status.

7When constructing an advanced PES (Problem-Etiology-Signs/symptoms) statement for a patient with cirrhosis-related sarcopenia, which formulation is BEST aligned with AND standardized terminology and supports targeted intervention?

A.Sarcopenia related to old age as evidenced by low muscle mass.

B.Inadequate protein intake related to early satiety from ascites and hepatic encephalopathy as evidenced by 24-hr recall protein of 0.6 g/kg and quadriceps wasting on NFPE.

C.Malnutrition due to liver failure.

D.Poor appetite related to cirrhosis as evidenced by weight loss.

Explanation: A high-quality PES statement uses standardized AND terminology for the problem (nutrition diagnosis), pinpoints a modifiable etiology (so the intervention targets the cause), and lists measurable signs/symptoms. 'Inadequate protein intake' is a recognized diagnosis; the etiology (ascites + HE) is modifiable, and S/S are quantifiable. Vague statements like 'malnutrition due to liver failure' are not actionable.

8A 78-year-old long-term care resident has lost 8% of usual body weight over 3 months, eats less than 50% of meals for more than a week, and has temporal and quadriceps wasting on NFPE. Per AND/ASPEN criteria in the context of chronic illness, this patient meets criteria for:

A.Non-severe (moderate) chronic-disease-related malnutrition

B.Severe chronic-disease-related malnutrition

C.Acute illness or injury related severe malnutrition

D.No malnutrition; findings are age-related

Explanation: AND/ASPEN chronic-illness severe thresholds include weight loss greater than 5% in 1 month, greater than 7.5% in 3 months, or greater than 10% in 6 months; energy intake less than 75% for greater than or equal to 1 month; and moderate-to-severe muscle wasting. This patient meets multiple severe criteria. Two or more characteristics are required to diagnose malnutrition.

9Which physical finding is MOST consistent with vitamin C deficiency on NFPE?

A.Bitot's spots on the conjunctiva

B.Perifollicular hemorrhages and corkscrew body hair

C.Koilonychia (spoon-shaped nails)

D.Glossitis with magenta tongue

Explanation: Perifollicular hemorrhages and corkscrew/coiled hairs reflect impaired collagen synthesis and capillary fragility from vitamin C deficiency (scurvy). Bitot's spots indicate vitamin A deficiency, koilonychia suggests iron deficiency, and a magenta tongue points to riboflavin deficiency.

10A patient with stage 4 sacral pressure injury has tunneling and undermining. According to NPIAP staging, which feature MOST distinguishes a stage 4 injury from unstageable injury?

A.Stage 4 injuries have full-thickness skin loss with visible bone, tendon, or muscle, while unstageable injuries are obscured by slough or eschar

B.Stage 4 injuries are always larger than 5 cm

C.Unstageable injuries always involve infection

D.Stage 4 injuries heal more rapidly than unstageable injuries

Explanation: Per NPIAP, stage 4 pressure injuries have full-thickness loss with exposed/palpable bone, tendon, fascia, muscle, or supporting structures; unstageable injuries also have full-thickness loss but the wound bed is obscured by slough or eschar so depth cannot be confirmed. Nutrition support for both follows similar protein/calorie targets (1.25-1.5 g/kg protein, 30-35 kcal/kg).

About the RDN-AP Exam

Advanced practitioner credential from CDR for senior Registered Dietitians demonstrating expertise across complex clinical nutrition practice. Beyond the standard RD/RDN, the RDN-AP validates synthesis-level competency in advanced nutrition assessment (NFPE, body composition, GLIM operationalized), management of combined-disease states (e.g., CKD + CHF + DM, oncology + sepsis on CRRT, transplant + steroids), advanced nutrition support (refeeding syndrome, IFALD, home PN), and the systems-level competencies (research/EBP, QI methodology, ethics, billing for MNT, leadership, advocacy) expected of a senior clinician. Eligibility requires demonstrated advanced practice via graduate degree, research/publication, or specialty certification.

Questions

150 scored questions

Time Limit

3 hours

Passing Score

Scaled

Exam Fee

Per CDR (CDR)

RDN-AP Exam Content Outline

44%

Nutrition Assessment and Diagnosis

Patient factors, NFPE, body composition, GLIM, AND-ASPEN, advanced diagnosis

38%

Nutrition Intervention, Monitoring, and Evaluation

Advanced intervention design, EN/PN, pharmacology/DNI, transitions

18%

Management of Systems

Systems design, technology/informatics, EBP/research, QI, billing/MNT, ethics, advocacy

How to Pass the RDN-AP Exam

What You Need to Know

Passing score: Scaled
Exam length: 150 questions
Time limit: 3 hours
Exam fee: Per CDR

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

RDN-AP Study Tips from Top Performers

1Master NFPE: identify subcutaneous fat loss (orbital, triceps fold), muscle wasting (temporal hollowing, deltoid squaring, prominent quadriceps wasting), edema staging, and micronutrient physical findings — these operationalize GLIM phenotypic criteria

2Know GLIM diagnosis: requires 1 phenotypic (weight loss >5% in 6 mo, low BMI, reduced muscle mass) AND 1 etiologic (reduced food intake/assimilation, inflammation acute/chronic). Severity by phenotypic magnitude

3Memorize refeeding syndrome management per NICE: identify at-risk (BMI <16, weight loss >15% in 3-6 mo, no nutrition >10 d, low pre-feeding K/P/Mg); start at 5-10 kcal/kg/d advancing over 4-7 d; replete K/P/Mg + thiamine 200-300 mg PO/IV BEFORE initiating feeds

4Understand IFALD prevention/treatment: cycle PN when feasible (≥12-hour off period), use omega-3-based lipid emulsions (SMOFlipid 1-1.5 g/kg/d, Omegaven 1 g/kg/d for established IFALD), reduce manganese, monitor LFTs

5Know CMS MNT benefit: covered for diabetes and CKD (non-dialysis) per Medicare Part B; CPT 97802 (initial individual 15 min), 97803 (re-assessment 15 min), 97804 (group 30 min); requires physician referral; expanded scope under MNT Act if passed

Frequently Asked Questions

How is RDN-AP different from a CDR specialty (CSO, CSP, CSR)?

RDN-AP is an ADVANCED PRACTITIONER credential — not a topic-specific specialty. It validates senior-level synthesis and judgment across the full breadth of clinical nutrition practice, integration of complex multi-system disease, leadership, and the systems-level competencies (research, QI, ethics, billing). Specialty credentials (CSO, CSP, CSR, CSG, CSPCC, CSSD, CSOWM) validate depth in a single practice area. Many advanced practitioners hold both.

What are the unique eligibility requirements?

Beyond the RD/RDN credential and 2,000 hours of post-RD clinical nutrition practice within 5 years, you must demonstrate ONE of: (1) graduate degree (master's or doctorate in nutrition or related field), (2) recent research presentation at a national conference, (3) peer-reviewed publication, OR (4) clinical specialist certification (CSO, CSP, CSR, CSG, CSPCC, CSSD, CSOWM, CDCES, CNSC). The advanced-practice demonstration is what distinguishes RDN-AP from a standard RDN.

When is the RDN-AP exam offered?

Unlike most CDR specialty exams which are offered year-round, the RDN-AP is offered in TWO testing windows per year. Plan well in advance — application and eligibility verification take time and you must be approved before scheduling with PSI.

What is NFPE and why does it matter?

Nutrition-Focused Physical Exam (NFPE) is a structured physical assessment for nutrition status. It identifies subcutaneous fat loss (orbital, triceps), muscle wasting (temporal, deltoid, pectoralis, quadriceps, calves), edema (NPIAP staging), micronutrient deficiency physical findings (angular cheilitis B2/B6, glossitis B12/folate, koilonychia iron, bitot's spots vit A, perifollicular hemorrhages vit C, follicular hyperkeratosis A), and helps operationalize GLIM phenotypic criteria. NFPE is heavily tested on RDN-AP.

How should I study for the RDN-AP exam?

Plan 80-120 hours over 10-14 weeks. The exam tests integration and judgment more than recall — practice complex case scenarios that combine multiple disease states. Master NFPE, GLIM operationalized, advanced nutrition support (refeeding NICE protocol, IFALD, home PN), advanced critical care nutrition, ethics in EOL artificial nutrition decisions, EBP critical appraisal (GRADE, PICO), QI methodology (PDSA), and CMS MNT billing. Use ASPEN, ESPEN, AND, GLIM as core references.