Clinical Chemistry Flashcards
Common enzymatic glucose measurements in serum
Oxidase
Hexokinase
Dehydrogenase
Common Anticoagulants
Heparin Sodium Fluoride EDTA Oxalate Iodoacetate Citrate Sodium
Normal GTT
Rises to peak then restores to the first level
Decreased GTT
Rises to peak and remains high
Elevated CSF glucose level
Increased permeability of meninges
Normal CSF (compared to plasma level)
60% of plasma level
Source of Error of glucose test
Hemolysis Lipemic Time of collection Time of serum separation Inappropriate anticoagulant use
Excretion site of Creatinine
Entirely by Glomerulus
Not significantly secreted or reabsorbed by tubules
Increased serum creatinine
Impaired renal function (50-60%)
Serum Creatinine level
- 6-1.1 mg/dl
0. 5-0.8 mg/dl
Urine Creatinine level
8-20 g/24hr
6-18 g/24hr
Synthesis of Urea
Liver; CO2 and Ammonia (deamination of amino acid)
Excretion of Urea
90% excreted through kidney
Freely filtrated by glomerulus
40% passively diffused from tubule
Increased Urea (BUN)
Increased protein intake/synthesis
Decreased kidney function/excretion
Dehydration
Decreased Urea (BUN)
Decreased protein intake/synthesis
Decreased liver function (Ammonia to Urea conversion)
Indirect method of Urea determination
Hydrolysis of urea with urease to determine amount of ammonium ion
Adult Serum BUN range
6-20 mg/dl
Newborn Serum BUN range
3-25 mg/dl
Urine BUN range
12-20 g/24 hr
Uric Acid formation
End product of purine metabolism by liver
Uric Acid excretion
Readily filtered by glomerulus
Undergoes a complex cycle of reabsorption and secretion by the tubules
Decreased Uric Acid level
Kidney disease
Increased Uric Acid
Gout
Liver disease
Adult serum Uric Acid level
- 5-7.2 mg/dl
2. 6-6.0 mg/dl
Synthetic function of Liver test
Albumin
PT
Bilirubin
Hepatocyte Injury test
ALT (Alanine Transaminase)
AST (Aspartate Aminotransferase)
Cholestasis liver test
Bilirubin
ALP (Alkaline Phosphatase)
Mild inflammation of liver
Reversibly increase permeability of cell membrane
Cytoplasmic AST, ALT
Necrosis of liver
Mitochondrial AST
Location of ALP
Liver Bone Placenta Kidney Intestine Surface of bile duct epithelia
Indicator of liver synthetic function
Bilirubin
Albumin
Prothrombin
Use of Antigen tests
Early diagnosis of infectious disease
Use of Antibody tests
Diagnose microbial disease
Screen donor blood
Monitor effectiveness of treatment
Direct HCG agglutination test
Reagent coated with anti HCG mixed with urine
Indirect HCG method
Detects prevention of agglutination of HCG-coated latex particles by HCG present in the urine
Strip HCG test
Reaction between HCG in urine and gold coated antibody on the strip
Factors that affect pregnancy test
Miscarriage (within 4 weeks) HCG injection Blood in urine Soap in container Diuretics Medication
False positive Widal test
Past infection
Cross reaction with other disease
Improper technique, handling
False negative Widal test
Early typhoid cases
Laboratory personnel
Poor antigen preparation, transport and storage
HIV test algorithm
Sequence of assays performed to detect HIV antibody in body fluid
3 tests of HIV algorithm
KHB (NR - negative)
Stat Pak (R - positive)
Unigold
