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Basic biochemical parameters in clinical
practice
Spring 2023
Department of Pharmacology and Toxicology
Faculty of Pharmacy MU
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Inflammation, Infections
Acute Phase Proteins
̶ Their levels in serum may be increased (positive APP) or reduced (negative APP) after the
onset of a systemic inflammatory reaction
̶ Produced in response to cytokine production
̶ Early acute phase proteins
̶ C-Reactive Protein (CRP), procalcitonin (PCT), serum amyloid A (SAA)
̶ Acute phase proteins with a moderate response time
̶ α1-acid glycoprotein, α1-antitrypsin, haptoglobin
̶ Slow-reacting acute phase proteins
̶ Complement C3 and C4
̶ The change in concentration occurs also non-specifically in many other conditions (reaction
of the organism to trauma, surgery, cancer etc.)
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C-Reactive Protein
̶ Plasma ß2-globulin that activates complement system
̶ Produced in the liver in response to tissue damage, infection or other inflammatory stimuli
̶ Biomarker of inflammation and cardiovascular risk
̶ CRP is not a specific marker of infectious disease
̶ The concentration increases in 6–9 h with a maximum in 24–48 h
̶ In healthy individuals – values <1 mg/L
̶ Virus infection – values ​​up to 40– 50 mg/L (usually lower – up to 20 mg/L)
̶ Bacterial infection – values >40–50mg/L (more specific in the presence of fever)
̶ Increase of CRP levels in postoperative conditions, cancer and inflammations in general
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C-Reactive Protein
Indications:
̶ To distinguish the type of pathogen (bacterial x viral origin) and the degree of immune
response
̶ To monitor the effect of antibiotic therapy
̶ To monitor the progress of autoimmune diseases
̶ But in patients with liver failure may be observed low CRP values
̶ Slower rising of CRP levels in the elderly
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Erythrocyte Sedimentation Rate
̶ Indirect measurement of the degree of inflammation (non-specific marker
of inflammation) – measurement of the rate of fall (sedimentation) of
erythrocytes
̶ The rate rises and falls more slowly than do CRP concentrations
̶ Normal ESR values are specific to age and sex
̶ The rate increases steadily with age and is higher in women than in men
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Procalcitonin
̶ New biomarker for early detection of (systemic) bacterial infections
̶ After immune stimulus, its serum concentration increases within 2–3 hours
̶ Higher sensitivity and specificity to distinguish systemic and local infection than CRP
̶ There is no significant increase in its concentration in viral infections, in autoimmune
diseases, postoperatively, in cancer
̶ More suitable (than CRP) in patients with weakened immune system, severe hepatic
insufficiency and in corticosteroid therapy
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Imunoglobulins
➢ IgG
̶ The largest proportion of total immunoglobulins
̶ Formed in response to toxins, the products of bacterial lysis, post-vaccination and after
viral infections
➢IgA
̶ Are used mainly in the defense of the mucosal surface infections
̶ The increase is often found in inflammatory conditions affecting the mucous membranes
and toxic hepatopathies
➢IgM
̶ Are formed mainly during the early response to bacterial and viral infections; their synthesis
is usually later replaced by IgG synthesis
̶ An increase in IgM is observed in some autoimmune diseases
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Hepatic dysfunction
̶ Liver injury of various etiologies (i.e., viral, metabolic, autoimmune, etc.)
̶ Cirrhosis can result in hepatocyte loss, which affects the liver’s ability to metabolize and
excrete drugs
̶ Determinants in how liver dysfunction affects pharmacokinetics:
➢ hepatic intrinsic clearance of the drug (= biotransformation)
➢ hepatic extraction ratio of the drug (= efficiency of the liver to remove a drug from the
systemic circulation)
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Effects of hepatic dysfunction on
pharmacokinetic processes
̶ Cirrhosis reduces the hepatic metabolism and clearance capacities:
➢ Cell damage reduces both the quantity and the quality of cells responsible for intrinsic
hepatic clearance
➢ Fenestrations in the sinusoidal endothelium can occlude, basement membranes can form
barriers between the sinusoid and hepatocytes → limitation of drug uptake into hepatocytes
➢ ↓ plasma protein synthesis → effect on drug protein binding → ↑ proportion of unbound drug
concentration
→ significant alterations in the exposure to many drugs, necessitating dosage adjustment
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Child-Pugh score
̶ Most common system for assessing the prognosis of chronic liver disease, primarily cirrhosis
̶ Scoring of five clinical biomarkers of liver disease:
➢ total bilirubin
➢ serum albumin
➢ prothrombin time or INR
➢ ascites
➢ hepatic encephalopathy
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Assessment of hepatic damage
ALT = alanine aminotransferase
̶ Cytoplasmic enzyme – role in the synthesis, degradation and conversion of amino acids, in
gluconeogenesis etc.
̶ Mostly in hepatocytes (intracellular enzyme) – when the cell membrane is damaged →
release into the blood
̶ Determination of serum ALT activity is marker of hepatocyte damage caused by
hepatocellular diseases
̶ Specific indicator of liver diseases – infectious (e.g., acute viral hepatitis), liver cirrhosis, liver
tumors, obstructive jaundice, toxic liver damage (drugs ampicillin, clofibrate, statins,
contraception, dicumarol, codeine etc.)
̶ The rate of the increase levels reflects the extent of the damage
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Assessment of hepatic diseases
AST = aspartate aminotransferase
̶ ↑ activity of AST in myocard, liver, skeletal muscles etc. (in general in all tissues with high
metabolic activity)
→ ↑ levels of AST is not a specific marker (serum activity is most increased in case of severe
hepatocyte damage)
̶ ↑ levels can be observed in:
̶ Liver diseases e.g., hepatitis – acute viral, chronic, other; liver cirrhosis, liver tumors, toxic
liver damage (drugs), myocardial lesions, skeletal muscle damage, conditions after heart
surgery etc.
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Assessment of hepatic diseases
AST / ALT ratio
̶ The serum AST / ALT activity ratio serves as a prognostic indicator
̶ Range of 0.5–0.8 – in acute and chronic viral hepatitis
̶ > 1 – non-alcoholic liver cirrhosis
̶ The highest values ​​are found in alcoholic liver damage
̶ Results > 1 may also indicate muscle damage (myocardial infarction, muscular dystrophy)
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Drug-induced liver injury (DILI)
̶ Intrinsic DILI
̶ dose-related
̶ occurs in a large pro-portion of individuals exposed to the drug (predictable)
̶ onset is within a short time span (hours to days)
̶ E.g., paracetamol, amiodarone, antimetabolites, cyclosporine, valproic acid etc.
̶ Idiosyncratic DILI
̶ usually not dose-related, although a dose threshold of 50–100 mg/day is usually required
̶ occurs in only a small pro-portion of exposed individuals (unpredictable)
̶ exhibits a variable latency to onset of days to weeks
̶ E.g., allopurinol, amiodarone, dantrolene, diclofenac, disulfiram, isoniazid, fenofibrate,
methyldopa, nitrofurantoin, phenytoin etc.
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Drug-induced liver injury (DILI)
̶ Acute fatty liver – clinical syndrome of rapid development of liver and other
organ failure associated with extensive microvesicular steatosis (amiodarone,
didanosine, stavudine, valproate, zalcitabine)
̶ Drug-associated fatty liver disease – non-alcoholic fatty liver disease
attributable to exposure specific medications (methotrexate, 5-fluorouracil,
irinotecan, tamoxifen, corticosteroids etc.)
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Standard liver biochemistry to assess
suspected DILI
̶ Absence of specific diagnostic biomarker
̶ ALT, ALP and TBL are the standard analytes to define liver damage and liver
dysfunction in DILI
̶ Alanine aminotransferase (ALT) – hepatocellular damage
̶ Total bilirubin (TBL) – cholestasis, impaired uptake, conjugation or
excretion, biliary obstruction, haemolysis
̶ Alkaline phosphatase (ALP) – cholestasis, infiltrative disease, biliary
obstruction; not specific (bone, salivary glands, intestinal, biliary)
̶ Etc.
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Creatinine
̶ The product of muscle energy metabolism (product of creatine and creatine phosphate
cleavage)
̶ The main source of creatinine is muscle tissue (98% of creatine is found in the muscles),
therefore the plasma concentration of creatinine is largely dependent on the muscle mass of
the individual
̶ Under physiological conditions, creatinine is excreted specifically by glomerular filtration
(90%)
̶ Its values in serum and urine to assess Glomerular Filtration Rate
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Glomerular Filtration Rate
̶ GFR (Glomerular Filtration Rate) = a key indicator of renal function
̶ Rate at which fluid is filtered across the glomerular basement membrane into
the renal tubules
̶ GFR is generally accepted as the best overal index of kidney function
̶ GFR <60 mL/min/1.73 m2 = decreased GFR
̶ GFR <15 mL/min/1.73 m2 = kidney failure
̶ eGFR is estimated GFR and is a mathematically derived entity based on a
patient’s serum creatinine level, age, sex etc.
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Glomerular Filtration Rate
̶ The reference values ​​for GFR (creatinine) according age:
20-40: 78 to 150 mL/min
40-50: 75 to 132 mL/min
50-60: 69 to 120 mL/min
60-99: 66 to 114 mL/min
̶ Relationship of GFR and creatinine concentration is not linear​​: the
value of GFR can be estimated from about 20 different equations
involving various corrections, or using other parameter, particularly
cystatin C
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Albuminuria
̶ Assessment of albumin levels in the urine
̶ Earliest marker of glomerular diseases, it generally appears before the
reduction in GF
̶ Normative values for albuminuria and proteinuria are in general expressed as
the urinary loss rate
̶ Urinary loss rate of albumin = albumin excretion rate (AER)
̶ The normal value – cca 10 mg/24 hours
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Cystatin C
̶ Physiological significance: cysteine ​​protease inhibitor, a protein
with MW 14 000
̶ Freely filtered through the glomerular membrane with subsequent
reabsorption, a small amount is also excreted in urine of healthy
individuals
̶ In clinical diagnosis:
reduction in glomerular filtration = ↑ CC in serum
renal tubular dysfunction = ↑ CC in urine
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Chronic Kidney Disease (CKD)
= abnormalities of kidney structure or function present for more
than 3 months
̶ Criteria (present for > 3 months):
➢ Decreased GFR – GFR < 60 mL/min/1.73 m2
➢ Albuminuria – ≥ 30 mg/24 hours
➢ Urine sediment abnormalities
➢ Electrolyte and other abnormalities due to tubular disorders
etc.
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Complications connected with CDK
– Drug toxicity
= complication, which is of relevance to all patients with CKD and reduced GFR
̶ Altered pharmacokinetics of drugs excreted by the kidney
̶ Increased risk of drug-interactions
→ Risk of errors in dosing, toxicity to the kidney (→ AKI) or systemic toxicity
→ Requirement of an adjustment in the dosage of many drugs
̶ At lower GFR – also changes in pharmacokinetics and pharmacodynamics of drugs not
excreted by the kidney
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Cautionary notes for drug administration in
people with CKD
Examples:
̶ NSAIDs – Avoid in people with GFR <30 mL/min/1.73 m2; not recommended in people with GFR
<60 mL/min/1.73 m2
̶ Aminoglycosides – Reduce dose and/or increase dosage interval when GFR <60 mL/min/1.73
m2, monitor serum levels (trough and peak), avoid concomitant ototoxic agents (furosemide)
̶ Macrolides – Reduce dose by 50% when GFR <30 mL/min/1.73 m2
̶ Fluoroquinolones – Reduce dose by 50% when GFR <15 mL/min/1.73 m2
̶ Sulfonylureas – Avoid agents that are mainly renally excreted
̶ Cisplatin – Reduce dose when GFR <60 mL/min/1.73 m2, avoid when GFR <30 mL/min/1.73 m2
̶ Methotrexate – Reduce dose when GFR <60 mL/min/1.73 m2, avoid, if possible, when GFR <15
mL/min/1.73 m2
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Acute Kidney Injury (AKI)
̶ Abrupt decrease in kidney function
̶ Various etioliogies – specific kidney diseases (e.g., acute interstitial nephritis, acute
glomerular and vasculitic renal diseases); non-specific conditions (e.g, ischemia, toxic injury)
etc.
̶ AKI is defined as any of the following (SCr = Serum creatinine) :
➢Increase in SCr by ≥0.3 mg/dL (≥26.5 μmol/l) within 48 hours; or
➢Increase in SCr to ≥1.5 times baseline, which is known or presumed to have occurred
within the prior 7 days; or
➢Urine volume <0.5 ml/kg/h for 6 hours
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Drug-induced acute kidney injury
̶ Acute tubular necrosis – aminoglycosides
̶ Osmotic nephrosis – e.g. hypertonic solutions
̶ Interstitial nephritis – acute allergic (penicillins), chronic (calcineurin
inhibitors), papillary necrosis + decreased intrarenal blood flown (inhibition of
prostaglandin-induced vasodilation) (NSAIDs), glomerulonephritis
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Lipids, lipoproteins
̶ Major lipids in plasma: fatty acids, triglycerides, cholesterol and phospholipids
̶ Triglycerides (triacylglycerols)
̶ From dietary fat, synthesis in liver and other tissues
̶ Source of stored energy (lipolysis hydrolysis catalyzed by lipases)
̶ Cholesterol
̶ Component of the cellular membranes, precursor of steroid hormones, bile acids, vitamin D3
̶ In plasma, lipids are transported in association with proteins:
̶ Free fatty acids with albumin
̶ In complexes as lipoproteins
➢Core – hydropfobic; triacylglycerols, cholesteryl ester
➢Outer layer from phospohlipids (outer hydrophilic part), cholesterol, apolipoproteins
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Lipoproteins
Classification od lipoproteins
Lipoprotein Source Density
(g/ml)
Function Risk of
atherosclerosis
Chylomicrons
(CM)
Intestine < 0.95 Transport of
exogenous
triglycerides
----
(CL remnants ↑↑)
VLDL Liver 0.96 – 1.006 Transport of
endogenous
triglycerides
↑
IDL Catabolism of VLDL 1.007 – 1.019 Precursor of LDL ↑↑↑
LDL Catabolism of VLDL
Via IDL
1.02 – 1.063 Cholesterol transport ↑↑↑
HDL Liver, intestine, catabolism
of CM and VLDL
1.064 – 1.21 Reverse cholesterol
transport
↓↓↓
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Lipids, lipoproteins
̶ Reference values (adults):
Total CH: up to 5.2 mmol/L (up to 5.8 mmol/L for individuals over 40 years old)
HDL-CH: male: over 1.1 mmol/L female: over 1.3 mmol/L
LDL-CH: 1.2 - 4.5 mmol/L
TG: 0 - 25 years old: up to 1.4 mmol/L
25 - 50 years old: up to 1.55 mmol/L
over 50 years old: up to 1.7 mmol/L
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Dyslipidemia
̶ Medical condition of an abnormal level of blood lipids
̶ Results from increased synthesis or decreased catabolism of lipoprotein particles
̶ which ensure the transport of fatty substances (cholesterol, triglycerides, phospholipids and
fatty acids)
̶ The clinical consequence of DLP is atherosclerosis
̶ Part of a condition called metabolic syndrom
→ co-occurence of cardiovascular risk factors as:
atherogenic dyslipidemia (hypertriglyceridemia + reduced high-density lipoprotein
cholesterol (HDL)), elevated fasting glucose, obesity and hypertension
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Glycemia
Reference value: adults 3.3–5.6 mmol/L
Diagnosis of diabetes mellitus (DM):
1) fasting blood glucose level exceeds 7 mmol/L in 2 separate visits
2) individual testing exceeds 11.1 mmol/L
3) after 2 hours in "oral glucose tolerance test" exceeds glycemia exceeds 11.1 mmol/L
If fasting glycemia < 7 mmol/L, and simultaneously in "oral glucose tolerance test" after 2
hours glucose still exceeds 7.8 mmol/L (but less than 11.1 mmol/L) = impaired glucose
tolerance
→ self-monitoring of blood glucose in DM
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Glycated proteins
̶ modified proteins that are formed by the addition of glucose molecules to amino acid chains
̶ Glycated hemoglobin (HbA1C) is an important glycated protein assayed to diagnose and
monitor diabetes
→ reflects long-term glycemic status
̶ HbA1C is used in routine as the best parameter to assess compensation of patients with DM
(efficacy of the treatment)
→ an indicator of so-called "long-term blood glucose" because it provides information on blood
glucose for a period of 2-3 months
Acute Coronary Syndrom (ACS)
= AMI with or without ST elevation (EKG), unstable angina
pectoris
hypoxia - necrosis
Biochemical investigation
enzymatic markers: creatinkinase, lactate dehydrogenase
non-enzymatic markers : troponin, myoglobin
Creatinkinase (CK)
3 cytosolic isoenzymes : CK-1 (CK-BB), CK-2 (CK-MB), CK-3 (CK-MM) a 1 mitochondrial (CKMt),
3 genes coding subunits CK-M, CK-B a CK-Mt
The most significant: total CK, CK-2 (CK-MB )
CK-MM is the most abundant isoform of CK in both heart and skeletal muscle, CK-MB is more
specific for heart
- heart: total CK consists of about 20% CK-MB
- skeletal muscle: total CK consists of 2% CK-MB (reflects status in healthy individuals)
AMI: increased enzymatic activity both total CK and CK-2 as well, but CK-2 is raised relatively
much higher than total CK
Skeletal muscle damage: increased enzymatic activity both total CK and CK-2 as well, and the
ratio between total CK and CK-2 is identical to healthy individuals
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High-sensitivity Troponin (hs-Trop)
̶ detection of myocardial infarction
̶ detects much lower concentrations of the troponin protein →
shortening the time interval required to identify myocardial injury
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Thank you for your attention