Banfi Flashcards
(156 cards)
1
Q
Turn around time
A
Period of time from collection of the biological material uni the production of test results and their interpretation
Includes three phases: pre analytical, analytical and post analytical
2
Q
Preanalytical phase
A
Involves the collection, transportation and storage of the biological material
Procedures performed by a nurse and this process also involves the choice of material for collection, patient preparation and preparation of the sample for the analysis
3
Q
Patient preparation
A
- Sample should be collected after 8-12 hours of fasting. if on fasting, it can induce turbidity in the serum (lipemic sample). A lipemic sample could also negatively influence and disturb optical methods using in the lab . It can also modify lab parameters like glucose, electrolytes and lipids
- Sampling must be carried out after 15 mins of rest and sitting position - physical exercise can modify some parameters (eg. creatinine kinase and electrolytes)
- Environmental conditions such as anxiet can also influence lab parameters, particularly hormones
- The position can also modify the hematocrit.
Drugs should be taken AFTER collection of the sample
4
Q
Trendelenburg position
A
Putting the patient supine and lifting the legs by 10% increases the hematocrit by 8% in 20 minutes, reducing the modification of plasma volume
5
Q
Hematocrit
A
Percentage of the blood represented by the corpuscular part (erythrocytes, leukocytes and platelets)
Athletes have increased plasma volume and consequent decreased hematocrit - known as sport anemia
6
Q
Tourniquets
A
Increase the volume of veins to facilitate blood drawing
Prolonged tourniquet use can cause stasis (leakage of liquid towards the extravascular compartment with an increase protein concentration and transported substances)
7
Q
Functional tests
A
Series of blood drawings
Used for oral glucose tolerance in diabetes
Also used in endocrinology, such as for the Growth hormone evaluation, or LH/FSH
8
Q
Needles
A
Caliber and predictable facility need to be taken into consideration
Correct needle avoids the stagnation of blood. Too rapid blood flow can also lead to hemolysis
Big vein - big needle
eg.
18G –> blood donations
Needles are supported with either rigid support or on butterfly
Inserted at a 20 degree angle, almost parallel to the vein itself
9
Q
Capillary blood
A
Mostly arterial blood - used in diabetic patients to measure glucose and lactate in athletes
Through fingertip or earlobe
Avoid squeezing - this increases interstitial fluid
10
Q
Arterial blood
A
Only for the analysis of blood cases
Usually taken from th write using a syringe, or from the radial/femoral artery
Technical difficulty + higher risk of hematoma + higher hydrostatic pressure compared to veins
11
Q
Anticoagulants
A
- EDTA and citrate, which bind to calcium ions needed in the coagulation cascade
- Heparin, which in habits thrombin
12
Q
CSF
A
Ultrafiltrate - no proteins
Present in the meninges
Withdrawal through a lumbar puncture
SMALL quantities - 4mL only
Used to evaluate the presence of leukocytes, glucose concentration (60% in CSF)
13
Q
Transudate
A
Represents liquids physiologically present in serous tissue
Edema.- increased liquid, so increased transudate
Also increases when oncotic pressure is decreased
14
Q
Exudate
A
Transudate + proteins
High protein concentration - more than 3g/L
Contains lactate dehydrogenase. Presence of high LAD means inflammation or infection
You can measure: glucose, tumor markers or inflammation markers
15
Q
Synovial fluid
A
Synovium
Presence of GAG and hyaluronic acid means high viscosity
Collected through articulate puncture
Rich in fibrin
16
Q
Amniotic fluid
A
Trans-abdominal puncture of the amniotic sac - 12th week of gestation
Genetic investigation of the fetus
17
Q
Semen
A
Subject must practice abstinence from ejaculation for 3 days
Sperm is collected through masturbation
Optimal temp. = 32 degrees
Measure: morhology, morphology and vitality
18
Q
First morning urine
A
Evaluate them up to 5 hours later
Bacteria growth can occur, certain components can also be destroyed, pH can be altered
19
Q
24 hour urine sample
A
Collection of urine samples over a period of 24 hours for certain parameters
Evaluate creatinine clearance - used to evaluate kidney function
Discard the first urine of the day
Storage at 4 degrees to prevent bacteria growth - sterility is important
20
Q
Feces
A
Used for the analysis of parasites
Evaluated through an occult blood test
Can measure calprotectin, for the monitoring of IBD like Corhns
21
Q
Saliva
A
Transudate
Enzymes, and hormones
Method of collection: Cottom is chewed, roll is inserted into a tube and then centrifuged
22
Q
Hair
A
Mainly for toxicology - evaluate the presence of drug abuse (alcohol)
23
Q
Urea breath test
A
Evaluate the presence of helicobacter pylori - generates an increase in the acidity of the stomach
Breath tests can also be done for lactose intolerance (release of hydrogen)
24
Q
Violet tube
A
Contains EDTA
Whole blood collection and CBC
25
Fundamental parameters
Erthyrocytes
Leukocytes
Platelets
Hemoglobin
26
Light blue cap
Citrate, used to assess coagulation factors
Coagulation: prothrombin time (PT) and partial thromboplastin time (PTT)
27
Black cap
Citrate but at a different concentration - one part for every.4 parts of blood
Erthrocyte sedimentation rate - used to evaluate inflammation
28
Green cap
Heparin - to obtain plasma
29
Grey cap
Very high accuracy - monoiodoacetate to block glycolysis - used to measure glucose very accurately
30
Red, yellow and orange cap
Dry tubes with no anticoagulants - used to obtain serum
31
EDTA
Ethylene diamine - used as an anticoagulant
Collects calcium ions to block the proteases needed in the coagulation cascade
32
International normalized ratio
Measurement of prothrombin time (PT) who are taking anticoagulant medication
33
Chronobiology
Science of biological rhythms - can be circadian, ultradian (shorter than one day - for elderly and newborns) or infradian (longer than one day)
circannual: eg. vitamin D which increases during summer when there is more sun - winter is the nadir
Crucial for maintaining homeostasis
34
Acrophase
Highest point of the circadian rhythm - moment in which the peak value occurs
Also known as zenith
Nadir is the lowest level
35
Amplitude
Quantity of the biological rhythm
36
Mesor
Rhythm adjusted mean value in chronobiology
37
Chronobiology synchronizers
Endogenous factors: hypothalamus
Exogenous: synchronizers
Primary synchronizer is the light dark cycle
Also defined by social behaviors, such as physical activity, timing and sleep behavior
38
Precision
Agreement amongst repeated measures
Measured through the coefficient of variation - the lower the CV the more precise it is
If imprecision is high there is a higher risk of incorrect diagnosis
39
Repeatability
Precision within the series - same lab, same method, same biological materials
40
Reproducibiility
Even when there is modifications of some conditions the test remains precise
41
Accuracy
Correlation between the mean of the values and the true values
Inaccuracy is also known as bias - difference between obtained mean value and the true value
True values are determined using reference methods (eg. mass spec. is very accurate for the evaluation of one molecule)
42
Analytical sensitivity
The minimum amount of detectable substance by using a specific method
Gets more important the smaller the molecule, eg. PTH and ferritin
Depends on the method used in the lab
Chemiluminecscne is the most sensitive method
Less sensitive methods can induce a delay in treatment and diagnosis
43
Specificity
Used to measure only the constituents to be measured
Interference is the measure of specificity - the higher the interference the lower the specificity
This is important for some type of family molecules such as cholesterol derivatives (ie. differentiating steroids)
It is also important for proteins - they all have the same alpha subunit but different beta chains
44
Clinical sensitivity
Calculated based on two groups - healthy and diseased
True positives, false positives
true negatives, false negatives
From this we can calculate positive and negative predictive values
45
Positive predictive value PPV
Percentage evaluating the correlation between positive values and the presence of the disease
46
Negative predictive value NPV
If the parameter is absence or is present within the negative range of values, we are sure that the disease is not present
47
Linearity
Approximation of a curve to a straight line
Used to find the analytical range
48
Calibration
Used to correlate the analytical responses with the concentration of a parameter
Provides a curve through which we evaluate the biological fluid obtained and deduce the number of parameters present in the sample
49
Matrix
medium in which the compound is located - important for commutability of materials
50
Random error
Expressed by coefficient. of variation - precision error
51
Systematic error
Because of bias - based on accuracy/trueness
52
total error
Sum of systematic and random error - accuracy
53
Internal quality control
Constant monitoring of the performance of the analytical system
In this case, the concentration of the materials is already known, and we accept results in real time
54
Analytical variability
Variability of analytical methods - should be less than biological variability
Optimal goal - when analytical variability is less than 1/4th of the biological variability
55
Biological variability
Variability of individuals - can't be influence
Cyclical variability of biological rhythms thet can't be influenced by the lab
Important for reference intervals - based on specific populations
56
Quality control
1. Control materials: stability, homogeneity, commutability - to evaluate the quality of measurements
2. Analysis of materials
3. Statistical analysis
57
Decision values
Thresholds indicating changing from physiological to pathological states
58
External quality control
Organizer of the quality control is outside the lab - the concentration of the materials is not known
Enables us to compare the results in an analytical series
Organizers distribute samples, receive results and evaluate them
eg. country/region government
Used for accuracy reference, and is a surrogate of the true value
59
Total difference
Analytical plus biological variability - used to calculate the critical differnece
60
Critical differnece
Basis for the calculation of significant differnece
Indicates if a given external factor has changed the parameter that we observed
CD works at a threshold - if exceeded it proves that the external factor influences the parameter
61
Electrolytes in plasma concentration
Plasma electrolyte content is different than intracellular electrolytese content
Cations:
- Sodium - 140mmol/L (fundamental for osmotic pressure)
- potassium - 4.5mmol/L
- calcium - 2.5mmol/L
- magnesium - 1mmol/L
Anions:
Chlorides - 102mmol/L
Bicarbonates - 27mmol/L
Proteins, sulphates etc.
Organic acids are present ONLY in the plasma and are completely absent in intracellular fluids
62
Constituents of intracellular fluid
Most important cation is potassium - 160mmols/L and magnesium
Proteins are four times more concentrated than in the plasma
63
Osmolarity
Number of osmoses in a given volume of solvent
Main osmoticallyy active substances beside electrolytes are glucose and urea
In healthy individuals osmolarity is 295mmol/L
64
Potassium
98:2 intracellular to extracellular
Maintained by ATP pump - important for resting membrane potential
Serum potassium is 3.5-5mmol/L
Decreased: hypokalemia - hyperinsulinism/cortisolism/aldosteroism - changes in ECG, muscle weakness, tetany, spasms
Increased: hyperkalemia - necrosis, hemolysis, acute renal failure, acidosis, hypothermia - arrhythmia, higher than 8mmol/L is very dangerous
During acidosis there is an increase in extracellular potassium
For each 0.1 change in ph there is a variation of 0.6mmol/L of potassium - its equilibrium is maintained by the kidneys
65
Sodium pathologies
Isotonic hyponatremia - pseudohyponatremia --> sodium is diluted because of high protein levels
Hypertonic hyponatremia --> because of hyperglycemia, leading to increased osmolarity
Hypotonic hyponatremia --> depletion of sodium due to vomiting/diarrhea
hyponatremia determines hypotonic blood and decreased osmolarity. it also induces edema
hyponatremia can also occur because of inappropriate ADH secretion - also is the first phase of acute renal failure
66
Hypovolemia
State of low extracellular fluid because of sodium and water loss - increased ADH production
67
How to measure sodium and potassium levels
Emission flame photometry - ISE
Flame photometry measures the concentrations of sodium and potassium present in 1L of serum, direct potentiometry can measure ionic activities in 1 liter of water
68
Calcium metabolism
Correlated to inorganic phosphate
Eliminated by the kidney, and a small part is released in urine
50% is ionized, 40% is bound to proteins, of which 85% to albumin
This binding is dependent on pH - when pH decreases ionized calcium increases
10% of calcium forms complexes with citrate or phosphate
Only free or ionized calcium influences the secretion of PTH, which controls calcium metabolism
Its levels follow the circadiann rhythm, with its max at 10am
69
Calcium reference range
2.1-2.6mmo/L or 8.4-10.4 mg/dL
70
PTH
Hypercalcemic hormone - increase calcium concentration by stimulating renal resorption in the tubules of the nephron
it also increases the absorption of calcium by hydroxylation of vitamin D in the intestines
increased calcium means decreased absorption of phosphates
71
Calcitonin
Produced by C cells in the thyroid, it is hypocalcemia (opposite of PTH)
72
Vitamin D
Determines calcium absorption in the intestines
below 20ng/mL is considered a vitamin D deficiency
20-30 --> administration of vitamin D by therapy or foods
optimal values are between 30-68ng/mL
73
Calcium pathologies
Decreased in hypoparathyroidism, deficiency of vitamin D, decrease of albumin, chronic renal failure, acute pancreatitis etc.
- Leads to excitability and tachycardia
Hypercalcemia - characterized by severe neurological symptoms and frequent urination (polyuria)
74
Phosphate
Fundamental for energy metabolism
Reference internal: 1.5-1.8mg/L
75
Magnesium
Second most important cation - coenzyme in many enzymatic reactions
Reference interval: 1.05-1.7 mol/L
Found in the plasma either bound to proteins, free or ionized
76
Magnesium pathologies
Hypomagnesemia: use of diuretics r drugs promoting magnesium degradation. Can lead to arrhythmia, and in severe cases symptoms within the CNS
Hypermagnesemia: from excessive intake through integrators rich in magnesium
77
International unit
An arbitrary unit to measure enzymatic activity
It corresponds to a micromole of substrate transformed in one minute at a defined temperature, pH and substrate concentration
The unit of measurement is the Katal (cat)
78
Factors affecting catalytic activity
Concentration
Temperature
pH
Inhibitors or activators
Quality of the enzyme
79
Types of enzymatic reactions
Zero type: when the speed is independent from the concentration of the substrate
First order: The reaction rate is proportional to the concentration of substrate
80
Classification of enzymes
- Plasma enzymes - decrease during pathology, are physiologically present in the plasma. For example, enzymes used in the coagulation cascade, or responsible for homeostasis
- Exoenzymes: enzymes secreted in natural cavitities/tubes eg. digestive enzymes
- Endoenzymes: enzymes involved in metabolism within the cell, altered during altered permeability of the membrane or during cell necrosis
81
Factors influencing enzymatic activity
1. Quantity of enzymes
2. Volume of distribution of plasma
3. Speed of removal of these enzymes from the blood
4. Factors inhibiting the activity of the enzyme
82
Transaminases
1. Aspartate transaminase - found in many different tissues but mainly the liver, heart and muscles.
reference range is between 10-50 units/liter. Increases suggest liver problems (eg. acute hepatitis). Acute alcoholic liver disease also is high levels of transaminases
2. Alanine transaminase - found mostly in the liver
83
Lactate dehydrogenase
Catalyze the last reaction of anaerobic glycolysis - to specific enzyme
Has overall low specificity so it is not used for diagnosis
84
Alkaline phosphatase ALP
Present in different tissues such as bone, liver, liver ducts, intestine etc.
Increases can be due to physiological growth, an abnormal action of osteoblasts, hyperthyroidism, metastasis and cholestasis (where the flow of bile from the liver to the duodenum is impaired)
85
Cholinesterase
Plasma enzyme secreted by the liver
Decreases of these enzymes is typical in hepatic diseases or nutritional deficiencies
Increases can be because of nephrosis
86
Gamma-glutamyl transpeptidases (GGT)
Mainly present in the liver but also in the kidney - its a marker for cholestasis
Used to evaluate toxic substances, such as alcohol abuse or some drugs
It is thus an indicator of toxic substances, alcoholism and cholestasis
In alcoholism, yGT is associated with a more specific parameter - carbohydrate deficient transferrin (CDT)
Nowadays, to evaluate chronic alcohol abuse we use the urine concentration of ethyl glucuronide
87
Creatinine kinase
Present in skeletal muscle - catalyzes the phosphorylation of creatinine from ATP
3 iosenzymes:
- CKBB: in many tissues
- CKMB: Cardiac muscle
- CKMM: Skeletal muscle
An increase in CK can be caused by musclee diseases and can lead to ischemia, infarctions
Used to evaluate skeletal muscle diseases, muscle trauma, as well as heart attacks (although nowadays this is more troponin)
88
Amylase
Responsible for the digestion of starch - increased in acute or chronic pancreatitis
Amylase sometimes binds with immunoglobulins, forming a macro amylase
Chronic hyperamylasemia: malignant tumors, alcohol abuse, chronic liver disease and liver insufficiency
89
Lipase
Digestion of fats - used for the diagnosis and monitoring of acute pancreatitis
Chronic pancreatitis = amylase
Has a short Half life
90
Acid phosphatase
Particularly found in the prostate
Used to evaluate the activity of osteoclasts in bones - its 5th isozyme TRAP is typical of bone tissue
91
Diagnostic enzymes
Transaminases: ALT and AST
LAD
ALP
Cholinesterase
yGT and CDT
CK
Amylase
Lipase
Acid phosphatase
92
Enzymes to assess protein synthesis
Albumin
Haptoglobin
Cholinesterase
Coagulation factors
Fibrinogen
Ammonia
93
Albumin
3.5-5.5g/dL - represent 60% of our total protein amount
Low level of albumin is linked to insufficient hepatocytic function
94
Haptoglobin
Produced by the liver - sensitive to decrease in hepatic function
Breaks down free hemoglobin (which can damage kidney function)
Decrease in haptoglobin is an indexx for the decrease in protein synthesis
95
Coagulation factors
An Index of hepatic dysfunction
Decrease in hepatic protein synthesis decreases prothrombin time, which is used to evaluate the coagulation function
96
Fibrinogen
If decreases its a sign of decreased hepatic function
97
enzymes tested for cytolysis
We can perform numerous tests for cytolysis of hepatocytes - it leads to increases in ASTs, LAD and serum iron (due to ferritin)
98
Ammonia
Presenting small quantities in the blood - 45-80ug/dL
Derives from the deamination of amino acids - transformed into urea to be excreted out through urine
In cases of hepatic dysfunction, ammonia can't be converted to urea so there is an increase of ammonia
Accumulation of ammonia in the brain leads to hepatic coma, which is the last stage of hepatic diseases
Ammonia is thus used to evaluate the residual capacity of the liver to convert ammonia into urea
99
Bilirubin
Principal parameter of excretion
Normally 250-300mg are produced every 24hours, and most is derived from the hemoglobin of destroyed red blood cells (5-20% is derived from the bone marrow)
It is transported by albumin - indirect or unconjugated bilirubin> it travels to the liver where it gets conjugated and is released by the liver as bile
Total bilirubin = 1.2mg/dL
Increase in inefficient erythropoiesis means an increase in indirect bilirubin
Only a fraction of bilirubin is excreted through urine, as urobilinogen - responsible for the yellow color of urine
100
Prerenal proteinuria
Increased elimination of protein in the urine, because the amount of proteins filtered is over the physiological 1.5g/day
101
Glomerular proteinuria
Damage to the filter, due to inflammation or diseasee, producing over 15g of protein per day within the filtrate
102
Tubular proteinuria
Mechanism of reabsorption is affected - tubule is not able to reabsorb the proteins that passed through the Bowmans capsule
103
post renal proteinuria
Very big proteins, such as immunoglobulins are eliminated in the urine - this is characterized by an inflammation of th eurinary tract and post glomerular bleeding
104
Myoglobin
Present in the skeletal muscle where it binds to oxygen. Large amount of myoglobulin in the blood suggests necrosis of skeletal muscles
The color of urine changes to red/brown when the concentration of myoglobin is higher than 100mg/L
105
Hemoglobin in blood
If found in blood this is a sign of intravascular hemolysis - an autoimmune mechanism wherein erythrocytes are destroyed and hemoglobin is released
If the concentration is over 100 mg/L the urine will turn red
106
Haematuria
Characterized by the presence of intact erythrocytes within the urine - suggests a bleeding in the upper or lower urinary tract
107
Haemoglobinuria
Sign of pre renal proteinuria - there is intravascular hemolysis
Measured through immunological methods to discriminate between hemoglobin and myoglobin
eg. hemoglobin catalyzes TMB, which turns a strip green to blue
108
Bence Jones proteinuria
Bence Jones proteins are free light chains of immunoglobulin type K or lambda
its proteinuria occurs when there is a cancer - multiple myeloma, and the protein releases its free light chains into the urine
109
Nephritis vs. nephrosis
Nephritis refers to an inflammation, whereas nephrosis refers to a degeneration
110
Nephrosis characteristics
Nephrotic syndrome is characterized by proteinuria (>3.5g/day), hypoalbuminae and edema. In some cases there is also lipiduria, the presence of lipoproteins in urine
111
Nephritic conditions
Two typical conditions: proteinuria and hematuria
112
Proteinuria in pregnancy
This is a sign of preeclampsia and is characterized by an increase of blood pressure with proteinuria and edema
Could be1 very severe diseases during pregnancy
113
Micrproteins - tubular function
Microproteins are a marker of tubular function, since small proteins are filtered and completely reabsorbed at the PCT in physiological conditions
They are thus measured and used as markers to identify defects in tubular function
Eg. NGAL, which is used as a sign of AKI (Acute kidney insufficiency), or beta2-microglobulin (most used).
114
Diabetic nephropathy
In diabetes there is an alteration of the basement membrane of the glomerulus because of the hypertrophy of the cells - leads to a loss of selectivity of the ions
Values of albumin between 20-200mg/L can give early signs of diabetic nephropathy
In type I diabetes the symptoms don't manifest early, instead there is a sort of honeymoon period where there is an increase in GFR
115
Lipoprotein classification
Chlyomicrons (has a density of 0.9 - lower than water)
VLDL - density between 0.95 and 1.006
LDL - density between 1.006 and 1.063
HDL - density between 1.063 and 1.21
Content of triglycerides decrease as you go down (HDL and LDL have the most amount of cholesterol), but proteins are increasing as you go down
Apoproteins, found on the membrane of lipoproteins are very important for transportation because they are hydrophilic
A2 is the receptor for HDL
B100 is the receptor for LDL
116
Cholesterol
Produce about 2g/day, usually used for releasing bile
Total cholesterol is 110-200mg/dL
LDL should be lower than 140mg/dL
HDL should be higher than 65mg/dL in females and 55mg/Dl in males. Hal is the good cholesterol because it is transported back to the liber where it is eliminated by bile acids. Higher in women because of estrogen
117
Atheroma
Fatty substance accumulation on the inside lining of arteries
threshold for cholesterol is 5.2mmol/L
118
Complete blood count parameters (four)
Concentration of hemoglobin
Leukocytes - WBCs
Erythrocytes
Platelets
119
Leukocytes
Includes three categories: granulocytes, lymphocytes and monocytes
Granulocytes are further divided into: neutrophils, basophils and eosinophils
They are resented both as absolute values and percentages
70% are neutrophils, 20% lymphocytes
Inflammation of infection = neutrophil
Viral infection = lymphocytes
10^9/l
120
Red bloodd cells
Devoild of nucleus
10^12/l
hemoglobin (Hb) have a range of 12-14g/dL in males whilst it is 14-16 in females
121
MCV
Means corpuscular volume - corresponds to the mean volume of RBCs
Measured in the 10^-15 liters
Usually around 80-90 fL in healthy individuals
122
Ht
Hematocrit, percentage of the corpuscular portion repesentec by RBCs+WBCs+platelets
Known as packed cell volume PVC
123
Winthrop parameters
MCH and MCHC
124
MCH
Mean corpuscular hemoglobin - quantity of hemoglobin in picograms in each red blood cell - if the parameter is low it means that there is a different production of hemoglobin
125
MCHC
Mean corpuscular hemoglobin concentration - quantity of hemoglobin compared to hematocrit
Measurement of chromasia
If low, it means that there is a low concentration of hemoglobin within each erythrocyte
126
RDW
Red blood cell distribution width
Gives information about the volumetric and morphological variability f red blood cells - it is calculated through coefficient of variation
If higher than 15% it means that there is ansiopoitchilocytosis - different volumes and shapes of erythrocytes due to difficult production and maturation
127
NRBC
Number of nucleated red blood cels - physiological in newborns but pathological in adults
128
PLT
Acronym for platelets
Follows a logarithm distribution due to the peculiar origin of platelets from the fragmentation of the cytoplasm of megakaryocytes
129
RET
Measure of reticulocytes - young erythrocytes
Used for the evaluation of bone marrow production
130
IRF
Immature reticulocyte formation
131
Morphological changes of erythrocytes
Macrocytes, Microcytes, Spherocytes, elissocytes, erythrocyte sickle cells, schistocytes (fragmented), stomatocytes (central accentuated concavity), dadrocytes (teardrop ashaped), target cells (reduced content of Hb)
132
Giesma method
Staining method for blood
133
Insulin actions
- Increases cell membrane permeability to allow glucose to enter cells
- Modulates cell enzyme activity to promote glucose utilization
- Regulates blood glucose levels by avoiding hyperglycemia
- Promoting glucose use, making it a hypoglycemic hormone
- Inhibits lipolysis and gluconeogeennesis, whilst also promoting anabolic metabolism
134
Types of diabetes
Type I: autoimmune
Type II: Resistance to insulin
Gestational: during pregnancy
Certain infections or drugs/toxics can also induce diabetes
Endocrinopathies, where hyperglycemic hormones are very high can lead to the exhaustion of insulin production, leading to diabetes
135
Diagnosis of diabetes parameters
1. Fasting/occasional glucose - overnight fast or at random times
2. Postprandial blood glucose/oral glucose tolerance test (OGTT) - measures glucose afterr consumption of a specific amount of glucose
136
Monitoring of glucose parameters
1. Glycemic
2. Glycoslyated hemoglobin
137
Complications of diabetes parameters
1. Microangiopathy to measure microalbuminuria
2. Atherosclerosis: lipids and lipoprotein levels
3. Ketoacidosis: ketonuria and blood gases are checked
138
Fasting glucose
The fasting glucose should be less than 100mg/dL
Between 100 and 126 is impaired, above 126 is considered diabetes
Samples are placed in special tubes that acidify the sample with antiglyolytic agents
139
Oral glucose tolerance test - OGTT
After administration of 75g of glucose, 2 hours later, if the glucose levels is more than 200mg/dL than it is diabetes (normal is less than 140mg/dL
Low reproducibility and inter-indivudal variability make it a less popular diagnostic tool today
Gestational diabetes is diagnosed if higher than 126mg/dL
140
Glucose reference values
Between 3.5-5.6mmol/L
In the blood the concentration is about 10% lower than the plasma concentration
above 7mmol/L is considered pathological
141
Enzymes to evaluate glucose
Exokinase and glucose oxidase
Measured through UV light
142
Glycation
Glycation is proprpotional to the integral of the concentration of glucose - it increases when glucose is high and then the time of contact between high glucose and protein is long
It is a slow process and limited by the average life of the protein
143
Glycated hemoglobin
HBA1c - used to evaluate the average blood glucose level of a diabetic person over two moths
This process depends on the average level of blood glucose
The glycation process:
1. Schiff base formation
2. Amadori rearrangement kectoamina
Forms a glycated protein
Glycated hemoglobin is refereed to as HbA1c
If the proportion of HbA2 is higher than 3.5% we have thalassemia
Glycated hemoglobin is a marker for stable glycemic control - if higher than 6.5% ist is a decision making level for the diagnosis of diabetes
Unit of measurement is the molar ration of HBA1c to moles of total hemoglobin
Above 75mmol/mol is a poorly controlled diabetic patient, 40-53 is the thresholdd for a good control of diabetes
144
Ketoacidosis
Complication of diabetes type I
Leads to lipolysis because of the presence of glucosee that can't be used - leads to the acidification of blood
Leads to ketonuria
145
C peptide
More stable in plasma than insulin
Used to evaluate the residual ability of the pancreas to produce insulin (particularly in type II diabetes)
146
Autoimmunity markers for Type I diabetes
ICA, IAA, GAD, TA2, ZnT8
Most common is GADL Glutamine acid decarboxylase
147
Microalbumimnuria
Values less than 20mg/L are physiological, but higher than 200 is a disease state (reversible)
It is accompanied by the onset of diabetic microangiopathy - not reversible over 200 mg/L
Can manifest in urine through selective glomerular proteinuria
148
Secretion and release of proteins in urine
1. Physiological turnover
2. Increased turnover
3. Hypertrophy of tubular cells
Increases in lysosomal enzymes suggests heightened protein reabsorption, which could indicate the onset of neuropathy
Excretion: passive
Secretion: active, requiring ATP
149
Physiological threshold for urinary protein excretion
150mg/day
150
Urinalysis - visual examination
Qualitative exam
- Color
- Appearance
- Volume
151
Urinalysis chemical examination
Semiquantitative:
pH (a higher pH is observed during infection)
Glucose
Bilirubin
Nitres
Blood
Urobilinogen
Protein
Leukocytes
Creatinine
152
Microscopic examination of urine
WBC
Bacteria
Crystals
RBC
153
Green urine
Linked to jaundice
Sen in typhoid fever
154
Brown urine
Seen in congenital diseases
Indicate a high concentration of bilirubin
155
Black urine
Blackwater fiver or tropical diseases such as malaria
156
Crystals in urine
Calcium phosphate crystals in alkaline urine
Most common: Calcium oxalate in acidic urine
Urate crystals which form in acidic urine
Triplee phosphate, struvite, ammonium magnesium phosphate
