Biochemical Assessment Flashcards
Difference of static and functional test
Static:
• Measure the actual level of nutrient in the specimen
Examples: serum iron, white blood cells, or ascorbic acid level
Functional:
• Determine the sufficiency of host nutriture to permit cells, tissues, organs, anatomical systems, or the host to perform optimally the intended nutrient-dependent biological function
• Aim to measure the extent of the functional consequences of a nutrient deficiency
Major limitation of static tests?
Major limitation: recent dietary intake may affect the level
What does static tests measure?
- A nutrient in biological fluids or tissues, or
- The urinary excretion rate of nutrient or its metabolite
Urinary excretion of xanthurenic acid as a test of vitamin B6
Abnormal metabolic products in blood or urine arising from reduced activity of a nutrient-dependent enzyme
Hemoglobin for iron status, erythrocyte glutathione reductase for riboflavin
Changes in blood components or change in enzyme activities that depend on a given nutrient
Lymphocyte proliferation for protein-energy, zinc and iron
In vitro tests of in vivo functions
Tryptophan load test for vitamin B6
Load and tolerance tests and induced responses in vivo
Dark adaptation and taste acuity for vitamin A
Spontaneous in vivo responses
Sexual maturation for zinc, cognitive performance for iron, iodine, zinc and vitamin B12
Growth or developmental responses
What are factors that may confound the results of biochemical tests?
- Method-related limitations
- Sampling difficulties
- Subject-related factors
4 Health-related factors - Biological factors
Serrum Ferritin Level is a biochemical test for what stage of Iron Depletion?
Stage 1: depleted iron stores
Transferrin saturation and erythrocyte protoporphyrin is a biochemical test for what stage of Iron Depletion?
Stage 2: Iron deficiency with no Anemia
Hemoglobin and Mean corpuscular volume is a biochemical test for what stage of Iron Depletion?
Stage 3: Iron-deficiency anemia
What is the cutoff value of depleted iron stores for males and females less than 5y of age?
<12 ug/L
What is the cutoff value of depleted iron stores for males and females more than 5y of age?
<15 ug/L Serum ferritin level
What is the cutoff value of depleted iron stores in presence of infection for males and females less than 5y of age?
<30 ug/L Serum ferritin level
What is the cutoff value of severe risk of iron overload for males and females more than 5y of age?
> 200 ug/L Serum ferritin level
What percentage of serum transferrin is associated with iron deficiency
<16%
What is the cut-off value in defining elevated transferrin receptor level?
> 8.0 ug/L
What is the precursor of hemoglobin and becomes elevated when the iron supply is insufficient
It can be used as a screening test in children and adults
Erythrocyte protoporphyrin
Reference value of Mean Corpuscular Hemoglobin
24-36 pg
Normal range for MCHC
320-360 g/L (32-36 g/dL)
Normal range of MCV
80-100 fL
Serum retinol concentration of VAD
< 20 ug/dL (0.70 umol/L)
VAD is a public health problem if
• >5% or pregnant women with XN or
• >15% of preschool children have VAD
Cut-off values for serum concentration of Vit A
20-100 ug/L
What Vit A level in breast milk suggests that a child is at risk of VAD?
adeuqate Vit A for growth and development?
nursing child’s body reserve will increase?
< 10 ug/dL
> 20 ug/dL
> 40 ug/dL
