Week 10 Flashcards
Bones have what
types of muscle
-dense outer layer and inner spongy layer
-skeletal (voluntary) , cardiac and smooth
Osteoporosis
and symptoms
tests for clinical indications
diagnostic tests
decreased bone density = fragile bones
-in post menopausal women
-asym until fractures
clinical indications -bone mineral density tests
diagnostic tests - Ca and Po4 levels (assessing bone metabolism,
increased Ca = hyperparathyroidism
low Ca = osteomalacia
ALP, d25, Osteocalcin
Bone mineral density test - DXA - primary diagnostic tool = measures bone density with dual energy X ray , results are a T score
if you have less than -2.5 you have osteo
pagets and symptoms
clinical indications tests:
diagnostic tests
chronic diorder that disrupts normal bone remodeling = enlarged bones
bone pain, deformities fractures, can have hearing loss
clinical indications increased ALP
diagnostic tests - ALP marker of bone formation increased in Pagets , fractures and osteomalacia
Quality assurance about serum testing
and DXA
serum processed quickly otherwise there will be changes in the CA due to prolonged storage
-hemolysis can falsely increase Ca
DXA-calibrate regularly , proper training to avoid errors in measurement
Muscular dystrophies
symptoms
tests for clinical indications
diagnostic tests
genetic disorder that causes progressive muscle weakness and degeneration
symp- muscle wasting , hard to walk , breathing problems
clinical indication - genetic testing, CK level
diagnostic test : CK released when there is muscle damage, increased in muscular dys and myositis
genetic testing to look for mutations like dystrophin in Duchenne Muscular Dystrophy
Quality assurance with
CK
Genetic Testing
CK - hemolysis falsely elevates CK
Genetic testing - avoid false neg/pos- contamination control and validation of sequencing techniques
myositis
symptoms
tests for clinical indications
diagnostic tests
- muscle inflammation - autoimmune or infectious
symp - muscle pain, weakness,
clinical indicators - muscle biopsy, EMG, serum markers like CK and Aldolase
Diagnostic CK released when there is muscle damage, increased in muscular dys and myositis
Osteoarthritis
symptoms
tests for clinical indications
diagnostic tests
degenerative joint disease- cartilage and bone breakdown
Symp - joint pain, stiffness, especially if you havent been moving alot , reduced flexibility
Clinical indications- synovial fluid analysis , X rays
Diagnostic test-
synovial fluid - looks at viscosity, cell count, crystals diff between arthritis
Rheumatoid Factor
symptoms
tests for clinical indications
diagnostic tests
- autoimmune disorder causing chronic inflammation of joints
Symps- swollen, warm, tender morning stiffness that lasts more than 30 mins, systemic symptoms like fatigue
Clinical indications- RF, ACPA- anti-citrullinated protein antibody, ESR
Diagnostic - presence of autoAB supports diagnosis but is not specific
Quality assurance of RF testing and Synovial fluid testing
RF testing - variability means this test needs standardized materials and regular calibration
Syno Flui - needs proper handling to avoid degradation especially for crystals
Tendinitis
symptoms
tests for clinical indications
diagnostic tests
inflammation of the tendon due to overuse or injury
symp - pain at tendon especially when moving - swelling
clinical indication - imaging to assess soft tissue involvement , lab tests to rule out infection or systemic
diagnostic
Imaging for soft tissues evaluation
MRI for soft tissue and bone
QA for imaging and lab tests
imaging - proper calibration
operator experience
lab tests - hemolysis and improper storage affect CRP and ESR
Bursitis
symptoms
tests for clinical indications
diagnostic tests
inflammation of the bursa (fluid fill sac that reduces friction between tissue)
symps - pain, swelling, limited movement of affected area
clinical indication - imaging to assess soft tissue involvement , lab tests to rule out infection or systemic
diagnostic
Imaging for soft tissues evaluation
MRI for soft tissue and bone
CRP/ESR increased in inflammatory bursitis - especially if infection or systemic disease suspected
Osteomalacia
symptoms
tests for clinical indications
diagnostic tests
issue with bone mineralization that causes bone softening due to Vit D deficiency
symp- bone pain, muscle weakness, increased risk of fracture
clinical indications-look at CA, PO4, VD, PTH
Diagnostic - D25 deficiency if < 50nmol/L
PTH - increased in 2ndary hyperparathyroidism as seen in VD def
CA- LOW or normal
ALP - increased
Xrays good to show pseudofractures (zones of decalification)
Rickets
symptoms
tests for clinical indications
diagnostic tests
softening of bones with Vitd def but in children causing bone deformities
symps - delayed growth, spine pain, skeletal deformities (bow leg, deformed spine and pigeon chest, dental issues”
clinical indications-look at CA, PO4, VD, PTH
Diagnostic - (Vit D) D25 deficiency if < 50nmol/L
PTH - increased in 2ndary hyperparathyroidism as seen in VD def
CA- LOW or normal
ALP - increased
how does osteoporosis occur
when bone resorption by osteoclasts is faster then bone formation by osteoblasts = decreased bone density
found mostly in post menopausal women due to decreased estrogen which impacts bone remodeling
risk factors to osteoporosis
major - over age of 65, history of fractures, use of glucocorticods, issues with nutrient absorption , early menopause
minor - smoking , low body weight , loss of height , kyphosis,
people are unware they have osteo until a fracture happens
rheumatoid arthritis and hyperthyroidism.
how to treat osteo
ca and Vd supplements
hormone replacement
biphosphonates
teriparatide
How does Vit D deficiency impact CA and PO4
vitamin D deficiency impairs calcium and phosphate absorption from the intestines, resulting in increased PTH levels, which causes bone resorption and the release of calcium from bones
Causes and risk factors from Vit D deficiency
- inadequate sun exposure , dietary restrictions, obesity, impaired nutrient uptake
-GI diseases, liver diseases, and inherited conditions can also lead to osteomalacia and rickets by affecting the metabolism of vitamin D and phosphate.
how to treat rickets and osteomalacia
- correct underlying def
-Vit D and Ca supplements with increased sun exposure
-PO4 supplements and analgesics
CAI
PURPOSE
Specimen type
methodology
1 -3 mmol/L
-preferred for neonates
Purpose - free form of CA in blood needed for muscle contraction , nerve function and clotting CAI is 50% of Total Ca in blood
Hyper - hyperPTH, malignancy or Vit D toxicity
Hypo-hypoPTH, renal failure, Vit D def
Whole blood preferred - in heparinized syringe maintain anaerobic conditions
Plasma/serum- must be done quick to avoid pH changes (if pH decreases so does CAI)
-transport on crushed ice- inhibits glycolysis
-analyze in 30 mins
ISE- direct measurement - potentiometric
Quality issues when testing for CAI
pH sensitivity - CAI is pH dependent
Alkalosis falsely lowers while acidosis increases
minimal air exposure
Pre ana errors - delays can cause inaccurate results
look at asap or keep anaerobic at stable temp
CA
PURPOSE
Specimen type
methodology
2-3mmol/L- stored and released by sarcoplasmic reticulum
Total Ca includes ionzied and bound forms of CA- looks at overall CA status but not reflective of active status especially if you have altered protein binding
Hyper (twitching, tetany) /Hypo (depressive- slug) - like CAI for screening and followup of abnormal CA levels
Serum or Plasma- preferred
collect with EDTA FREE tubes so the anticoagulant doesnt chelate CA
Colorimetric assay - OCPC or arsenazo II dye binding method Abs change is proportional to concentration
Quality issues with measuring Ca
Protein binding -
Total Ca can be affected by ALB, so if there is hypoALB you need to correct the CA
Anticoagulant interference - EDTA and citrate can chelate CA which can cause falsely low results
MG
PURPOSE
Specimen type
methodology
0.6.-1
-levels in serum/plasma not specific
to one body system
-needed for enzyme function , neuromuscular activity and ca regulation from Scar retic , helps with metabolic processes
hypo- caused by malnutrition, chronic alcoholism and prolonged diuretic therapy , tetany, MI, renal loss, decreased gut absorption
hyper - seen in renal failure, excessive MG uptake or therapeutic use in preclampsia, found in antacids
serum or plasma - serum preferred
hemolysis will falsely increase
colorimetric assay - xylidyl ble and calmagite dye binding are used (total MG)
ISE used for FREE MG
Quality issues when measuring MG
Hemolysis - RBC have high MG so if hemolysis occurs it will falsely increase MG (intracellular like K)
ANTICOG - EDTA, cit, and Oxalate interfere with magnesium measurement - dont use
lipemia , jaundice interfere with reading
-acidify 24 hr urine container with HCL
PO4
PURPOSE
Specimen type
methodology
<0.1% of total body po4 is in plasma
-diurnal variation highest in the AM, fluctuates with exercise
-energy production, bone mineralization , cellular function. Regulated by the kidneys, VitD and PTH
hypo- malnutrition, chronic alcoholism and inherited disorders
hyper- CKD, hypo PTH, or excessive PO4 intake
-PTH increases PO3 in urine and lowers PO4 in serum
-Ca and P are inversely related
Serum or plasma - serum is preferred can use plasma but avoid ANTICOG that can chelate PO4
Colorimetric - PO4 reacts with molybdate to form a complex spectrophotometrically. proportional relationship
Quality issues when measuring PO4
Hemolysis - false increase in PO4 after release from RBC
Stability - analyze quickly
pH - reaction should be acidic
contamination - contamination from phosphate detergents ; use acid washed dishes
Vit D or D25
PURPOSE
Specimen type
methodology
-needed for Ca and Po4 homeostasis= bone health , increases intestinal absorption of Ca and P
-D25 marker for Vit D status
Deficiency - can cause rickets in kids, osteomalacia in adults and increased risk of osteoporosis
Toxicity - rare but with too much supplementation - causes hyperCA
Serum preferred
immunoassays- competitive binding like chemilumin ,
LC-MS/MS is gold standard
Quality issues with measure Vit D D25
Handling - stable as serum in RT for short time, must refrigerate for long term storage for accuracy
PTH
PURPOSE
Specimen type
methodology
-secreted by chief cells
-produced in response to low Free CAI
-targets bone and kidney and gut (since it stimulates production of Vit D)
- regulates Ca and PO4 in blood and influences bone metabolism needed to diagnose hyper/hypo PTH
-stimulates Osteoclastic activity
primary Hyper- increased PTH and Ca
hypo-low PTH and low Ca
serum or plasma- collected and store cold to prevent degradation . EDTA is preferred
immunoassay like two site or sandwich are most common to detect intact PTH
Quality issues with PTH
Stability - unstable at RT, can degrade quickly , immediate refrigeration and quick analysis
Cross - reactivity - PTH assays can cross react with PTH fragments = false increase
make sure you use specific assays for intact PTH
ALP
PURPOSE
Specimen type
methodology
-class 3 hydrolase with group specificity
- enzyme in tissues , highest conc in liver, bones, kidney and bile duct. use to assess bone and liver diseases
Bone disorders - increased in osteoblastic activity like Pagets, fractures, osteomalacia
Liver disease - increased in cholestasis, biliary obstruction and liver cirrhosis
serum fasting to avoid post prandial increase in ALP
colorimeteric assay - hydrolysis of p nitrophenyl phosphate that produces yellow product that you measure with a spec. change is proportional to ALP activity
-2-3 times greater than RI in 3rd trimester
-kids have 1-4 times more than adults
Quality issues with ALP measuring
Hemolysis - causes false ALP increase
temp - keep at RT and analyze with in 4 hours
pH controlled 10.3 very alkaline
kinetic or rate reaction
RI is age and sex dependent
ALP isoenzymes
PURPOSE
Specimen type
methodology
- differentiates the source of elevated ALP is it bone, liver, placental or intestinal
-measures BAP - expressed by osteoblasts when they start making new bone
Increased ALP to determine if bone (pagets) or liver (cholestasis)
Serum preferred
electrophoresis and heat inactivation - ID based on they mobility and heat stability
-immunoassay SPECIFIC for BAP - not used for diagnosis only monitoring
Quality issues when looking at ALP isoenzymes
Sample handling
improper handling and storage can alter isoenzyme patterns .
Calcitonin
PURPOSE
Specimen type
methodology
produced by para follicular cells (c cells) or thyroid . helps with ca and bone metabolism by inhibiting osteoclast activity by lowering CA levels. Tumor marker for medullary thyroid carcinoma MTC (increased)
hypercalcemia - calcitonin can be used with other markers to cause this
Used as a therapeutic agent for pagets
hypo-renal disease, fatty soaps from pancreatitis
Serum preferred - analyze quickly or it degrades
chemiluminescence or radioimmunoassay
(RIA) used - very sensitive and specific
antagonist to PTH
decreases Ca
Quality issues with Calcitonin
Assay interference - heterophilic AB, biotin can increase or decrease use blocking agents
Specimen stability - unstable in serum, keep cold or frozen and analyze quick to avoid degradation
reference range - vary with age, gender and lab method - use method specific RI and consider the above
CK
PURPOSE
Specimen type
methodology
found in skeletal muscle , heat, brain . Produces energy by catalyzing the conversion of creatine and ATP to ADP
MI - severe increase CK, - CKMD - heart damage
Rhabdomyolysis - severe increase due to muscle breakdown
Muscular Dystrophy - severe increase inherited disorders like Duchenne DMD have chronic elevations because of ongoing degradation
Myositis and Polymyo - inflammatory muscle diseases - increase
hypothyroidism - mild or mod increased due to muscle involvement in hypothyroid myopathy
severe increase over 5000U/L
mild increase after little muscle injury
Specimen type for CK and handling methodology
Serum - preferred - sst , clot and spin
Plasma - in heparinized tube but values may differ- need consistency
handling - analyze right away to prevent degradation can be refrigerated,
freeze thaw cycles can lead to loss of enzyme activity
enzymatic assay where CK catalyzes conversion of CKP and ADP to Cr and ATP with a 2ndry reaction that produces a change in ABs with NADH proportional to CK activity
Quality issues with CK testing
hemolysis - false increase as intracellular CK is released
Stability - CK activity decreases over time
test quick or refrigerate
non specific enzyme reactions can give background ABs = inaccuracies . Validate all methods so no cross reactivity or interference
Physical activity before test - significant increase - tell pts not to exercise before test
use lab RI - as it varies with age and gender
Osteoblasts
bone formation
make bone matrix
regulate Ca and P
differentiate into mature osteocytes (bone matrix)
Osteoclasts
-break down bone: resorption
-proteolytic enzymes & HCl demineralize & degrade bone matrix
-important role in bone remodeling & mineral
homeostasis
Bone Remodelling regulated by
- Metabolism of Ca, P & Mg (minerals)
- Hormones (PTH, Vitamin D, calcitonin, growth hormone, estrogen/osteoporosis)
- Enzymes (ALP)
- Cytokines: substance produced by one cell that effects function of another cell
- Genetics, diet, physical activity
Effect of PTH on bone:
increased
bone resorption: release of Ca and P into blood
Effect of PTH on kidney:
increased Ca reabsorption
decreased P reabsorption
increased 1,25(OH)2 Vitamin D
Effect of 1,25(OH)2 Vitamin D on intestine:
increased calcium-binding protein synthesis
increased Ca absorption in intestine
increased P absorption in intestine
how does Calcium need to be collected
without venous stasis (stopping of blood)
-if tourniquet stops TP falsely increases
-no clenching if fist
-lying down decreases CA
acidify urine container with 6 mol HCL for U24
store a few days at 4, plastic and glass can absorb Ca
critical if <2.10 or >2.10
-If ALB decreases so does CA
-hemolysis , jaundice, lipemia can falsely increase
urine mmol/d
serum mmol/L
bone formation marker
osteocalcin
made by osteoblasts
increased in bone diseases with bone turnover
-measure in serum with immunoassay
bone resorption markers
deoxypyridinium (serum)
❖ pyridinoline (serum)
❖ C-telopeptide (serum)
❖ N-telopeptide (serum or urine)
made by osteoclasts
-measure cross linking metabolites based on where they appear in the bone cycle
-associated with maturation of a bone
-If anti-resorptive drug therapy is effective, markers should decline within several months
