Biochemical Assessment Flashcards
Components to examine in a biochemical assessment
Visceral and somatic proteins
Hematological assessment
Lipid profile
Micronutrient assessment
Immunocompetence assessment
Consider: nutritional status, medication, illness/physiological state
Albumin normal range in SI units
Albumin mild, moderate and severe deficit values
Albumin normal: 35-50 g/L
Mild deficit: 30-35 g/L
Moderate deficit: 24-29.9 g/L
Severe deficit: <24 g/L
How is visceral protein status assessed?
What are the serum proteins and in what rough proportions?
By looking at serum proteins. RBC and WBC
Malnutrition –> ↓ organ mass –> ↓ serum protein synthesis in liver
Serum proteins: albumin 90%, fibronectin 5%, transferrin 5%, prealbumin .7% retinol-binding protein .3%
Serum proteins can be influenced by
Low protein intake
Altered metabolism/synthesis
Inflammation
Hydration status
Medications
Pregnancy
Exercise
Rank the serum proteins based on their efficacy as a biomarker
Shorter half life means faster turnover and a better biomarker
Retinol binding protein: 10-12 hrs
Prealbumin and transthyretin (TTR): 2-3 days
Transferrin: 8-10 days
Albumin: 17-21 days
Main functions of serum proteins and when they are high
Albumin: maintains osmotic pressure and transports insoluble molecules/drugs/Ca/Zn
High during: dehydration, corticosteroid use
- Low during acute illness: acute phase protein
Transferrin: Fe3+ transport
High during: Fe deficiency
TTR: transport of T3/T4 in complex with RBP
High during renal failure and Hodgkins disease
RBP: retinol transport from liver
High during renal failure
Name the acute phase serum proteins
Negative: albumin, transferrin, TTR, RBP decrease 25% during inflammation, illness and metabolic stress
Positive: C-reactive protein (CRP) elevation from 1 to >5 mg/L indicates mild or acute inflammation (non-nutritional - can help interpret negative proteins)
N balance equation
Urinary urea nitrogen mmol-g conversion
Nitrogen balances
N balance reflects protein retention/losses but not mass
N balance (g/day) = (g intake/6.25) - (UUN g + 4)
*UUN = urinary urea nitrogen
*+4 is the misc correction factor
*1 g N = 6.25g protein (16% N in protein)
1 mmol UUN = 0.028 g UUN
Positive balance –> anabolism>catabolism during pregnancy, growth, recovery, athletic training
Negative balance –> anabolism<catabolism during starvation, poor protein intake/type, trauma, surgery
Limitations of N balance
Time: 24 hr urine collection (ideal 3x24hr)
Errors in estimated vs measured protein intake
Incomplete urine collection
Does not account for diarrhea, vomiting, wound leakage losses
Errors favor positive balance (over-estimation of intake and under-estimation of losses)
Urinary creatinine measurement
When it is increased/decreased
Creatinine Height Index and interpretation
Urinary creatinine proportional skeletal muscle mass (creatine
not stored in muscles)
Increased due to: exercise, meat intake, menstruation, infection, fever, trauma
Decreased due to: renal failure and age
Normal excretion:
Women: 18 mg/kg
Men: 23 mg/kg
Creatinine Height Index: 24h creatinine (mg)/expected 24h excretion (mg)
Mild depletion: 60-80%
Moderate: 40-59%
Severe: <40%
*requires meat-free diet in advance
Clinical assessment includes
medical, social and psychological history: primary and secondary diagnoses, PMHx, WtHx, factors affecting nutrient intake and social history
physical examination for clinical signs/symptoms through visual inspection and palpation
Physical Signs of Malnutrition on face and mouth and their possible deficiency root causes
Hair: dry, dull, brittle, alopecia, early graying
–> protein, energy, zinc, Cu, EFA
Face: fullness, puffy, cheeks
–> protein, energy
Eyes: dry, pallor, corneal vascularization
–> Vit A, Fe, B vit
Lips: angular stomatitis, cheilosis
–> niacin, B2, Fe, B6
Tongue: magenta, painful, edema, smooth, taste change, glossitis
–> B vitamins, zinc, vit A, Fe
Gums/teeth: bleeding, receding, gingivitis, stomatitis, caries
Vit C, folate, B12, protein, energy, fluoride
Physical signs of malnutrition on the body and their possible deficiency root causes
Skin: dry, scaliness, slow wound healing
–> vit A, zinc, EFA, protein, vit C, biotin
Nails: spoon, egg shell
–> Fe, Cr, vit A
Musculoskeletal: wasting, weakness, bone pain
–> protein, energy, B1, Ca, vit D
Neurological: sensory, confusion, reflex depression, dementia, tetany
–> B1, B6, B3, B12, protein, Ca, Mg
Abdomen: distended, flatus
–> protein, energy, lactose intolerance
Environmental assessment components
Socioeconomic status, food security status
Education, nutrition literacy
Time and ability to cook
Work schedule, travel
Allergies, intolerances, restrictions
Cognitive function
Functional assessment
Muscle strength correlated with muscle mass –> predictive of malnutrition
Measure: hand grip strength using dynamometer 3x on dominant hand
- 23 kg (W) and 35kg (M)
- or gait speed, chair stand, ADL, IADL, self-reported activities
