Clinical tests and results assessment

2021-06-24 03:19 PM

Creatinine is a breakdown product of phosphocreatine, an important energy storage substance found in muscle. Creatinine production is relatively constant, depending mainly on the muscle mass of each person.

Outline

Clinical biological tests including the fields of biochemistry, haematology, immunology, microbiology, parasites, viruses are increasingly rich modern tools indispensable to help physicians in diagnosis, treatment, and monitoring of disease progression. Working in clinical pharmacy, pharmacists need to know the meaning and assessment of the results of several common clinical tests to help make the use of drugs reasonable and safe, and to promptly detect unwanted effects. during patient treatment. This chapter mainly deals with some biochemical and haematological tests.

SI system in medicine 

Blood, urine and some biological fluids are commonly used for analysis. Results obtained in healthy subjects are within certain limits called "normal values" or "reference values". Results outside the upper limit are called "abnormal". Each test can be analysed by different methods, so slightly different results may be obtained. Therefore, the physician should use the reference value made in his facility.

To unify the way results are expressed, over the past few decades many changes have been made to the use of the SI (système international) system of units. The SI system is based on 7 base units: meter (length), kilogram (weight), second (time), mole (amount of substance), Kelvin (temperature), ampere (amperage), and candela (light intensity).  

Base unit SI

Quantity

Name

Symbol

Length

Weight

Time

Amperage

Temperature

Light intensity

Amount of substance

met

kilogram

seconds

amp

kelvin

candle

mol

m

kg

s

A

K

Cd

mol

From these 7 base units, expand to other derived units such as: m2 - area, m3 - volume, Newton (N) - force, Pascal (Pa) - pressure, Joule (J) - work or energy, Hertz (Hz) - frequency. Thus, the gas pressure is not expressed in mmHg but in Pascal. When the base and derived units are of inappropriate magnitude in biological constants, multiples and decimal divisors of the units are used by concatenating the corresponding prefixes to the names. those units. 

Common prefixes in clinical testing

Prefix

Symbol

Coefficient

weight

mega

giga

mili

micro

nano

pico

femto

k

M

G

m

m

n

p

f

103

106

109

103

106

109

1012

1015

The main reason driving the conversion to the SI system comes from the fact that substances react with each other, molecule to molecule rather than gram to gram, thus expressing the substances in moles as reasonable and easier to compare than expressed in grams. Mol is a shortened noun for the molecule gram (molécule - gramme). For example, 1 mole of oxygen (O2) has a weight equal to 16 x 2 = 32g; 1 mole of glucose (C6H12O6) is equal to 180g (12 x 6 + 1 x 12 + 16 x 6). The molar unit is not used to express the very dilute concentration of glucose in the blood, but its divisor is millimoles: 1mmol glucose = 0.180g. For example, in 1 liter of normal human blood, there is about 5mmol glucose, which means 5 x 0.180g = 0.90g/l.

The concept of molarity does not usually apply to substances such as proteins and complex polyoxides whose molecular mass is unknown.

Regarding enzyme activity, the katal unit (symbol kat) is the amount of enzyme that catalyses the transformation of 1 mole of the substrate in 1 second(s) under certain test conditions. This unit is often too large, in clinical biochemistry often use smaller units such as microkat, or nanokat. These units gradually replaced the old international unit of enzyme (symbol U) which was the amount of enzyme that catalysed the transformation of 1 mmol of substrate per minute under certain test conditions.

The ions were previously expressed in equivalents: Na+, K+, Cl-, now in moles:

1mEq = 1mol/Chemotherapy

Percentages are replaced with decimals. For example: 0.50 instead of 50%; 1.15 instead of 115%.

How to convert to the SI system in medicine

Since 1977, the 30th World Health Assembly has decided to accept the use of the SI system in Medicine, but many documents and publications in the time of transition still use both old ways of expressing results. and new. There are conversion factors from the old unit to the new unit or vice versa (table).

Biochemical reference value of blood

Test

Reference value

Conversion factor

Old unit

New unit

Alanine amino transferase (TOOL, GPT)

0 - 35 U / l

0 - 0.58 mkat / l

0,01667

Albumin

4,0 - 5,0 g/dl

40 - 50 g/l

10

Aspartat amino transferase
(ASAT, GOT)

0 - 35 U / l

0 - 0.58 mkat / l

0,01667

Total Bilirubin

0,1 - 1,0 mg/dl

2 – 18 mmol/l

17,10

Direct Bilirubin

0 - 0,2 mg/dl

0 – 4 mmol/l

17,10

Kicks

8,8 - 10,3 mg/dl

2,20 - 2,58 mmol/l

0,2495

Total cholesterol

160 - 180 mg/dl

4,1- 4,6 mmol/l

0,02586

Cholesterol LDL

50 - 130 mg/dl

1,30 - 3,30 mmol/l

0,02586

Cholesterol HDL

30 - 70 mg/dl

0,80 - 1,80 mmol/l

0,02586

Total CO2

22 - 28 mEq/l

22 – 28 mmol/l

1

Chloride

95 - 105 mEq/l

95 - 105 mmol/l

1

Creatinin kinase (CK)

0 - 130 U / l

0 - 2.16 mkat / l

0,01667

Creatinin

0,6 - 1,2 mg/dl

50 – 110 mmol/l

88,40

Creatinine clearance

75 - 125 ml/min

1,24 - 2,08 ml/s

0,01667

Globulin

2,3 - 3,5 g/dl

23 - 35 g/l

10

Glucose

70 - 110 mg/dl

3,9 - 6,1 mmol/l

0,05551

Time

3,5 - 5,0 mEq/l

3,5 - 5,0 mmol/l

1

Lactat dehydrogenase

50 - 150 u / l

0.82 - 2.66 mkat / l

0,01667

Sodium

135 - 147

135 - 147 mmol/l

1

Osmol* (osmolarity of plasma)

mEq/l

280 - 300 mOsm/kg

 

phosphate

2,5 - 5,0 mg/dl

0,80 - 1,60 mmol/l

0,3229

Phosphatase acid

0 - 5.5 U / l

0 - 90 nkat / l

16,67

Phosphatase

30 - 120 U / l

0.5 - 2.0 mcat / l

0,01667

Whole Protein

6,0 - 8,0 g/dl

60 - 80 g/l

10

Transaminase (GOT)

see ASAT

 

 

Transaminase (GPT)

watch ALAT

 

 

Triglycerides

< 160 mg/dl

< 1,80 mmol/l

0,01129

Ure

20 - 40 mg/dl

3,3 - 6,6 mmol/l

0,165

Acid uric

2,0 - 7,0 mg/dl

120 - 420 mmol/l

59,48

* Osmol*: osmolalite plasmatique - the osmotic pressure of the plasma produced by sodium, glucose and urea/blood.

Some biochemical tests

Plasma creatinine (0.6 - 1.2 mg/dl; SI = 50 - 110 mmol/l)

Creatinine is a breakdown product of phosphocreatine, an important energy storage substance found in muscle. Creatinine production is relatively constant, depending mainly on the muscle mass of each person. Therefore, in women, plasma creatinine is slightly lower than in men. The plasma creatinine concentration is little changed, independent of extrinsic factors, e.g. diet. Creatinine is excreted in the urine mainly by glomerular filtration; The part excreted by the renal tubules or reabsorbed is very little, considered insignificant. Plasma creatinine is considered a better indicator of renal function than blood urea. As the glomerular filtration rate decreases, the plasma creatinine concentration increases. Considered renal failure when plasma creatinine is greater than 130 mmol/l. Creatinine clearance (clearance): in men 75 - 125 ml/min or 1.24 - 2.08 ml/s; in women is 85-90% of men. The clearance coefficient of a substance is the volume of plasma that the kidneys are able to clear out of the substance in 1 minute. In other words, it is the ratio of the amount of that substance in the urine excreted in one minute divided by the concentration of that substance in the blood plasma.

C = U/V

Inside:

Cl = clearance in ml/min.

U = concentration of the substance in the urine.

P = plasma concentration of the substance.

V = volume of urine in one minute.

In fact, it is considered a renal failure when the creatinine clearance is less than 80 ml/min. Renal failure was considered mild if the creatinine clearance was greater than 50 ml/min, moderate with values ​​between 15 and 50 ml/min, and severe with values ​​as low as 15 ml/min. There is a correlation between creatinine clearance and creatinine content (table).

Relationship between clearance and plasma creatinine

Creatinine clearance (ml/min)

Plasma creatinine (mmol/l)

100

50

25

12,5

110

220

440

880

Although creatinine clearance is a better measure of glomerular function than creatinine alone, its disadvantage is that it is difficult to perform clinically because it requires 24-hour or at least 8-hour urine collection. Therefore, there have been many formulas to convert plasma creatinine to clearance without collecting urine. The most commonly used is the formula of Cockroft and Gault which allows the estimation of this clearance factor:

CL ml/min = {(140 – Age) x Bodyweight}/ (Creatinin x 72)

Where age is in years, bodyweight is in kg, and plasma creatinine is in mg/dl. This is the value for men, when applied to women, multiply the result by 0.85. For patients with liver failure, the above formula cannot be used because it will give erroneous results.

Many drugs are completely or partially eliminated by the kidneys. Creatinine clearance is the basis to help adjust the appropriate drug dose by either reducing the dose for each dosing, or prolonging the interval between 2 doses, or a combination of these methods. . For example, in the case of ceftazidime, a 3rd generation cephalosporin antibiotic, the normal adult dose for intramuscular or intravenous injection is 3 g/day (1 g/ 8 hours). In case of renal failure adjusted as follows:

How to adjust the dose of ceftazidime in renal failure?

Creatinine clearance (ml/min)

Single-dose (g)

Times

50 to 30

30 to 15

15 to 5

< 5

1

1

1

0,5

1-2 times/24 hours

1 time/ 24 hours

1 time/ 36 hours

1 time/ 48 hours

 

Urea (20 - 40 mg/dl; SI = 3.3 - 6.6 mmol/l)

If expressed as blood urea nitrogen (BUN, blood urea nitrogen), the normal value is 8 - 18 mg/dl; SI = 3.0 - 6.5 mmol/l.

Urea is a major protein degradation product, formed in the liver and eliminated mainly in the urine. Hypouricemia is rare, usually in the end stage of liver failure due to impaired urea synthesis. High blood urea nitrogen (>50 mg/dl) may have prerenal, postrenal, or renal causes. Pre-renal causes such as dehydration, vomiting, diarrhoea, decreased blood flow, shock, heart failure. Post-renal causes such as urinary tract obstruction (stones). Renal causes such as acute or chronic glomerulonephritis, acute pyelonephritis due to toxicity. Normal urea clearance is about 75 ml/min because, after glomerular filtration, part of urea is reabsorbed by the renal tubules. In patients with renal failure, this coefficient decreases.

Glucose (fasting 70 - 110 mg/dl; SI = 3.9 - 6.1 mmol/l)

Glucose is the main source of energy for the brain and muscles. Blood glucose is always constant due to the neuroendocrine regulation mechanism. The hormones that regulate blood glucose are divided into two opposing groups: on the one hand, insulin-lowering hormones, on the other hand, hormones that increase blood glucose (adrenalin, glucagon, glucocorticoids, somatostatin). The most common is high blood sugar due to diabetes. Fasting blood glucose levels higher than 126 mg/dl (7 mmol/l) are considered pathological.

Blood sugar as high as 290 - 310 mg/dl (16 - 17 mmol) has a risk of causing a diabetic coma. However, it is not possible to state a specific limit because this value varies quite a lot with each case. Hypoglycaemia below 45 mg/dl (2.5 mmol/l) is also very dangerous. The cause is often related to mistakenly overdose of insulin in the treatment of diabetes.

In addition to diabetes, hyperglycaemia is also caused by several other endocrine diseases: Cushing's syndrome (hyperthyroidism), acromegaly, hyperthyroidism or drugs: glucocorticoids, thiazide diuretics, blockers b, phenytoin. Hypoglycaemia is also caused by several causes such as a pancreatic tumour, liver failure, hypopituitarism, hypothyroidism..., adrenal cortex insufficiency.

Acid uric (2 - 7 mg/dl; SI = 120 - 420 mmol/l)

Uric acid is the final degradation product of the purine nucleus and is eliminated mainly in the urine. Increased uric acid in the blood may be due to increased production (high nucleoprotein destruction, high protein diet) or poor elimination (nephritis). Serum is usually saturated with uric acid (at 7 mg/dl), if this threshold is exceeded, crystalline sodium urate can accumulate in cartilage, joints, and kidneys. It is a symptom of Gout. Lower urine pH, reducing the solubility of uric acid, can lead to stone formation. Agents with cytotoxic effects can increase blood uric acid (antagonists, some anticancer drugs such as methotrexate, busulfan, vincristine, prednisone, azathioprine). Agents that reduce renal tubular uric acid excretion also increase serum uric acid (thiazide diuretics, furosemide, ethacrinic acid).

Serum protein (6.0 - 8.0 g/dl; SI = 60 - 80 g/l)

Serum proteins analysed by electrophoresis are divided into albumin and globulin.

Albumin is the main protein, accounting for 60% of the total protein. Synthesized by the liver, albumin plays an important role in maintaining colloidal pressure and in the transport of many organic and inorganic compounds. Many water-insoluble drugs are highly bound to plasma albumin, eg phenytoin, salicylates, phenylbutazone, warfarin, first-generation sulfonylureas, valproic acid and some sulphonamides. Because the free drug is the active form, changes in albumin concentrations can greatly affect the distribution and pharmacological effects of the drug.

Globulin (2.3 - 3.5 g/dl; SI = 23 - 35 g/l). Globulin can be divided into several subtypes: globulin a1, a2, b, and g. Globulin g can also be broken down into many different immunoglobulins (IgG, IgA, IgM, IgD and IgE). The separation of globulins is useful in the diagnosis of many immunological diseases.

Total protein can be increased or decreased in many pathological conditions. Low cases (mainly albumin) are seen in malnutrition, digestive disorders, cancer, liver failure, cirrhosis. It is due to the deficiency in synthesis. Hypoproteinaemia is also due to increased excretion: Nephrotic syndrome, loss of protein in the urine a lot, blistering, loss through the skin... Hyperproteinaemia is seen in the case of haemoconcentration, due to dehydration and some diseases. globulin disorders: multiple myeloma (Kahler's disease), Wald Enstrom’s macroglobulinemia...

Enzyme

Enzymes localized in tissues are responsible for catalysing metabolic reactions in cells. When cells are destroyed, large amounts of enzymes are released into the serum. Measuring the activity of these enzymes helps assess tissue damage: The more extensive and acute the injury, the more enzymes are released into the bloodstream. Insidious chronic lesions usually release only moderate amounts of enzymes.

Isoenzymes or isozymes are enzymes that catalyse the same chemical reaction but they differ in some physicochemical properties. The distribution of isozyme varies from tissue to tissue. Therefore isoenzymes are also used to locate the lesion.

Enzyme activity is expressed in international units (U) or according to the SI system in katals (kat). One microkatal (µkat) is equal to 60u.

Creatin kinase (CK) or creatin phosphokinase (CPK)

(0 - 130 u / l, SI = 0 - 2.16 µkat / l)

Creatine kinase catalyses the conversion of phosphocreatine to creatin, releasing energy-rich phosphate mainly for cardiac and skeletal muscle: CK is a dime consisting of 2 subunits M and B. Brain tissue is about 90% BB (CK1) and 10% MM (CK3). Cardiac tissue is 40% MM (CK2) and 60% MM while normal serum is 100% MM as in skeletal muscle. Clinical events causing elevation of serum CK are usually from skeletal muscle or myocardium. The brain type BB is never found in the serum, even after a stroke, because this enzyme does not cross the blood-brain barrier.

Any injury to skeletal muscle tissue causes an increase in serum CK. Acute rhabdomyolysis due to trauma, prolonged coma, and overdosage of certain drugs can cause an increase in CK. Other musculoskeletal injuries such as muscular dystrophy, polymyositis, or hypothyroidism can also cause significant CK elevations.

CK is the earliest enzyme to increase in myocardial infarction. About 4 hours after the attack, serum CK begins to rise and peaks at about 24 hours and then returns to normal after the second to the fourth day. A CK-MB fraction above 6% of total CK enzyme activity is considered a sign of myocardial infarction. Many drugs used at therapeutic doses or overdoses have manifestations on skeletal muscle, increasing CK: Preparations with opiates, cocaine, amphetamines, theophylline, antihistamines, fibrates, barbiturates, some antibiotics, chloroquine, corticosteroids, vincristine. Lovastatin also causes rhabdomyolysis (0.5% of cases), especially when combined with gemfibrozil (5% of cases).

Aspartate aminotransferase (ASAT)

Also known as glutamate oxaloacetate transaminase = GOT, (0 - 35 u/l; SI = 0 - 0.58 µkat/l) is an enzyme that transports amino groups.

Concentrations of this enzyme are highest in heart and liver tissues, and less in other tissues. After CK, ASAT is the second enzyme to increase early in serum after myocardial infarction: increase begins after 6-8 hours, peaks after 24 hours and then returns to normal after 4-6 days. ASAT is elevated in liver diseases, particularly in viral or toxic hepatitis. In this case, serum ASAT and ALAT increased early before the clinical manifestations dozens of times higher than normal. In cases of chronic hepatitis, cirrhosis, or cholestasis, ASAT activity is moderately increased depending on the degree of cell destruction.

Many drugs can cause an increase in ASAT because of damage to liver cells, for example, isoniazid, especially when combined with rifampicin.

When continuing to take the drug and the enzyme continues to increase, for example, more than three times the upper limit of normal, the drug should be temporarily or permanently discontinued.

Alanine Aminotransferase (ALAT)

Also known as glutamate pyruvate transaminase = GPT, (0 - 35 u/l; SI = 0 - 0.58 µkat/l).

It is also an amino group transfer enzyme. ALAT is more abundant in the liver than in the heart, in contrast to ASAT. Although both enzymes are elevated in liver diseases, ALAT is considered a more liver-specific enzyme because it is rarely elevated in diseases other than the liver parenchyma.

Phosphatase (30 - 120u/l; SI = 0,5 - 2,0 µkat/l)

This is an enzyme that catalyses the hydrolysis of monophosphate esters with a pH up to pH = 9. This enzyme is present in many tissues but mainly in liver, bone and intestinal cells and is excreted in bile. Therefore, serum alkaline phosphatase is elevated in the presence of cholestasis. Some drugs that cause cholestatic jaundice, such as chlorpromazine or sulphonamides, also increase alkaline phosphatase. In mild acute liver injury, alkaline phosphatase is rarely increased. Even in cirrhosis, this enzyme level is erratic depending on the state of decompensation and biliary obstruction.

Osteoblasts in bone produce more alkaline phosphatase. Therefore, the activity of this enzyme is greatly increased in deforming osteomyelitis (Paget's disease) which can be up to 20-30 times higher than normal. In rickets, osteomalacia, hyperthyroidism, cancer metastases to bone, this enzyme is also increased. During periods of rapid bone growth in children, during fractures, and during pregnancy due to placental and fetal contributions, serum alkaline phosphatase activity may be increased.

There is also an acid phosphatase with an optimal pH in the range of pH = 5. This enzyme is found mainly in the prostate gland, red blood cells and platelets. The enzyme is often elevated in serum in cases of metastatic prostate cancer.

Bilirubin

In which: total < 1.5 mg/dl, direct < 0.5 mg/dl, SI = total < 26 µmol/l, direct < 8.6 µmol/l.

Bilirubin is a degradation product of haemoglobin. In plasma, bilirubin is transported as bound to albumin. Reaching the liver by glucuronyl transferase, bilirubin conjugates with two glucuronic acid molecules to become diglucuronic bilirubin. This type of conjugate is very serum soluble and is known as direct bilirubin or hepatic bilirubin. Unconjugated bilirubin is called free or indirect bilirubin or pre-hepatic bilirubin. Bilirubin conjugated with bile acids is stored in the gallbladder. When bile enters the intestines during digestion, intestinal bacteria convert bilirubin into urobilinogen and stercobilinogen. These products are colourless, continuing to transform in 3 ways:

Oxidized to urobilin and coloured stercobilin, mostly excreted in the feces.

Through the enterohepatic cycle, reabsorption is returned to the liver and then excreted in the bile.

A small part is excreted in the urine.

Causes of hyperbilirubinemia can be classified into three categories:

Before the liver (haemolysis)

In the liver (poorly or poorly conjugated bilirubin)

Post hepatic (bile duct obstruction).

When the serum bilirubin concentration is above 34 µmol/l, jaundice occurs. Haemolytic jaundice is caused by the destruction of red blood cells beyond the conjugation capacity of the liver. Neonatal jaundice is caused by a deficiency of the conjugate enzyme. Some drugs can cause haemolytic anaemia due to immune mechanism (methyldopa, penicillin, cephalosporin, quinidine, ibuprofen, triamterene) or oxidation mechanism of haemoglobin (dapson, some antimalarials, sulphonamides...)

Hepatocellular damage in viral or toxin-induced hepatitis often causes elevated serum bilirubin levels, mainly of the direct type, and very high transaminase activity, where ALAT is usually higher than ASAT. Some drugs can directly damage liver cells: Acetaminophen, halothane, tetracycline, valproic acid, isoniazid, rifampicin, methyldopa. Drug-induced liver injury may be indistinguishable from acute viral hepatitis. In alcoholic hepatitis, transaminase activity is usually only a fraction of that in viral hepatitis, ASAT is usually higher than ALAT.

Patients with obstructive jaundice often have white clay-coloured stools and dark urine because a lot of bile pigments are excreted in the urine, but not in the stool. Lack of bile acids in the gastrointestinal tract due to biliary obstruction causes steatorrhea - Transaminase is usually only slightly increased, alkaline phosphatase is very high. The most common causes of obstructive jaundice are gallstones and pancreatic cancer. Some drugs cause cholestatic jaundice: Oestrogen, chlorpromazine, erythromycin estolat...

Enzymatic changes in hyperbilirubinemia

Reason

Fecal bilirubin

Urine Bilirubin

Direct bilirubin
(% of total)

ASAT

TOOL

Phosphatase

Haemorrhage

 

-

< 20

Normal

Normal

often

Hepatocellular destruction
 (due to viruses or toxins)

¯

+

> 40

 

 

 

Cholestatic jaundice

¯

+

> 50

 

 

 

Cirrhosis due to alcohol

Normal

±

< 30

 

 

 

Some haematology tests

There are three types of blood cells in the blood: red blood cells, white blood cells, and platelets. Blood tests help diagnose and monitor disease progression, on the other hand, help monitor the effects of drugs including unwanted drug effects.

Red blood cell count

1mm3 of blood in men has 4,200,000 ± 200,000 red blood cells; female 3,850,000 ± 150,000 red blood cells.

The main function of red blood cells is to carry oxygen from the lungs to the tissues thanks to the role of haemoglobin (haemoglobin).

Normal Vietnamese haemoglobin concentration is: Male 14.6 ± 0.6 g/dl; female 13.2 ± 0.5 g/dl. Anaemia is considered when the haemoglobin level is less than 13 g/dl in men and 12 g/dl in women; but there are also cases of pseudo-anaemia due to increased plasma volume dilution.

Haematocrit

39 - 45% or 0.39 - 0.45 in men; 35 - 42% or 0.35 - 0.42 in women.

If the anticoagulated whole blood is centrifuged in a capillary tube, two parts will be separated: the liquid upper part is plasma, the lower solid part is blood cells. Comparing the percentage of blood volume to whole blood is called haematocrit. In fact, one compares the height of the 2 layers. Haematocrit decreases in bleeding and haemolysis and increases in dehydration due to persistent diarrhoea, vomiting, and fever.

Red blood cell index

These indices are used to classify anaemia.

Mean cell volume (MCV = mean cell volume).

MCV = Haematocrit/RBC count.

Normal is 88 - 100mm3 (88 - 100fl); 1 fl (femtolit) = 10-15 liters = 1 mm3.

< 80 fl = small red blood cells.

> 100 fl = macrocytic red blood cells.

> 160 fl = megaloblastic.

Mean cell haemoglobin (MCH = mean cell haemoglobin)

MCV = Haemoglobin/ Red blood cell count

Normal is 28 - 32 pg (picogam) = 1.8 - 2 fmol (femtomol).

Average haemoglobin concentration of red blood cells

(MCHC = mean cell hemoglobin concentration)

MCH = Haemoglobin/RBC count = MCH/MCV

Normal is 320 - 350 g/l = 20 - 22 mmol/l.

MCV allows the detection of changes in the size of red blood cells (small red blood cells, macrocytic red blood cells, giant red blood cells).

MCHC allows the determination of isochromatic, chromophore or hypochromic in all forms of anaemia. This indicator is somewhat more correct than MCH.

Here are the common anaemia states:

Hypochromic anaemia, small red blood cell size: Haemoglobin is much lower than the number of red blood cells; seen in anaemia caused by chronic bleeding, peptic ulcer, hookworm, haemorrhoids, malaria, iron deficiency diet.

Isochronic anaemia, normal red blood cell size: Haemoglobin decreases in parallel with the number of red blood cells, there is no change in red blood cell size; seen in acute bleeding, some cases of haemolytic anaemia, some infections, typhoid.

Hyperchromic anaemia, large red blood cell size: Haemoglobin is low compared to the number of red blood cells, in the blood see many giant red blood cells, macrocytic red blood cells - seen in Bireme’s anaemia, anemia state after cutting gastric bypass, pregnancy, cirrhosis, vitamin B12 or folic acid deficiency.

Certain drugs and chemicals (pyramidon, chloramphenicol, lead, benzene, X-ray) can cause anaemia due to poor or inactive bone marrow. This is usually isochromic or hypochromic, with small red blood cells. Some other drugs can cause haemolytic anaemia by allergic immune mechanism: beta-lactam, tetracycline, tolbutamide, chlorpropamide, quinine, rifampicin, primaquine, nitrofurantoin, sulfamethoxazole...

Reticulocytes (0.5 - 1.5% of red blood cells; SI = 0.005 - 0.015)

As a new erythrocyte with peripheral bleeding, after 24-48 hours, these red blood cells become normal red blood cells. After bleeding or haemolysis, this rate can be up to 30-40%, showing that the blood is being restored quickly. For iron, vitamin B12 or folic acid deficiency anaemias, with appropriate treatment, reticulocytosis is also seen.

Erythrocyte sedimentation rate (3-7 mm/hr in men; 5-10 mm/hour in women)

Erythrocyte sedimentation rate (sedation) is the rate at which red blood cells are deposited in blood that has been anticoagulated and aspirated into a capillary tube of certain diameter in an upright position. The height of the plasma column is usually obtained after the first 1 or 2 hours. Erythrocyte sedimentation rate is increased in inflammatory diseases such as rheumatism, active tuberculosis, cancer (the first hour may reach 30-60 mm). Although this test is not specific but simple, it is often used to monitor disease progression.

White blood cells (3200 - 9800/mm3)

White blood cells help the body fight pathogens by phagocytosis or by immune processes. Based on their shape and structure, white blood cells are divided into 5 types: neutrophils, polymorphonuclear leukocytes, basophils, monocytes, and lymphocytes. All three types of polymorphonuclear leukocytes have many characteristic granules in the cytoplasm, so they are also called granulocytes.

The formula for white blood cells in percentage is as follows:

Neutrophils: 50 - 70%.

Basophils: 0 - 1%.

Eosinophilic granulocytes: 1-4%.

Lymphocytes: 20 - 25%.

Monocytes: 5-7%.

A white blood cell count above 10,000/mm3, is considered leucocytosis. When the number falls below 3000/mm3, it is considered leukopenia.

Haematological reference number

Test

Reference value

Conversion factor

Old unit

Unit SI

Red blood cells

4,2 ± 0,2 x 106/ mm3

4,2 ± 0,2 x 1012/l

 

erythrocyte sedimentation rate  

- Male

- Female

 

3 - 7 mm/1 hour

5 - 10 mm/1 hour

 

3 - 7 mm/hour

5 - 10 mm/hour

 

1

1

Haematocrit  

- Male

- Female

 

39 - 45%

35 – 42%

 

0,39 - 0,45

0,35 - 0,42

 

0,01

0,01

Haemoglobin  

- Male

- Female

 

14,6 ± 0,6 g/dl

13,2 ± 0,5 g/dl

 

146 ± 6 g/l

132 ± 5 g/l

 

10

10

White blood cells

3.200 - 9.800/ mm3

3,2 - 9,8 x 109/l

0,001

Mean red blood cell haemoglobin (MCHC)

28 - 32 pg

1.8 - 2.0 rmol

 

Mean haemoglobin concentration of red blood cells (MCHC)

32 - 36 g/dl

320 - 360 g/l

10

Mean erythrocyte volume (MCV)

86 - 98 mm3/cell

86 - 98 rl

 

reticulocyte

0,5 - 1,5%

0,005 - 0,015

0,01

Neutrophils: (1100 - 7000/mm3)

Neutrophils contain many hydrolytic enzymes. Their role is phagocytosis. One neutrophil can phagocytize 5 to 20 bacteria.

Neutropenia (over 70%, possibly up to 95%) is seen in acute infections: pneumonia, appendicitis, tonsillitis, purulent diseases, abscesses, boils... Leukopenia neutrophil polymorphisms (< 1500/mm3) may be due to decreased reproduction or enhanced destruction. Seen in some infections such as typhoid, influenza, measles, HIV, malaria or due to certain drugs acting on DNA synthesis (phenothiazines, phenytoin, antibiotics, sulphonamides), cytotoxic drugs used in cancer, due to specific drug reactions (chloramphenicol, phenylbutazone, quinidine). There may be increased destruction of neutrophils by the immune system in patients receiving aminopyrine, phenylbutazone, or sulphapyridine. A severe condition is an agranulocytosis, which is characterized by a sudden very severe decrease in granulocytosis (< 200/mm3) with fever, ulcers,

Eosinophils (eosinophilia = 0 - 400/mm3)

Also capable of phagocytosis but much weaker than neutrophils. Increased in allergic diseases, asthma, eczema, parasitic diseases such as worms, flukes. Decreased in the following cases: shock state, Cushing's disease, complete bone marrow conditions.

Basophils (0 - 150/mm3)

Very rarely in blood. They are incapable of motility and phagocytosis. They also play a role in allergies: The antibody to allergic reactions, IgE, normally binds to the membranes of basophils and tissue mastocytes (mastocytes are basophils in tissues). When the specific antigen reacts with this antibody, it will cause the basophils, which bind IgE to break down and release a large amount of histamine, bradinin, serotonin... It is these substances that cause reactions at places such as oedema, rash, itching, pain. Basophils are increased in hypersensitivity, hypothyroidism and decreased in long-term corticosteroid therapy.

Monocytes (200 - 700/mm3)

After being born in the bone marrow, monocytes briefly enter the bloodstream and then enter tissues, rapidly becoming macrophages. In the blood, monocytes are immature cells that are not able to attack and destroy pathogens. Thus, monocytes and macrophages are different stages of the same cell type and form a system formerly called the endothelial reticulum, which is now the tissue macrophage system. Tissue-attached macrophages are called fixed macrophages and stay there for months or years. They can leave tissue to become mobile macrophages that travel to inflammatory areas by chemotaxis: Their function is phagocytosis, a macrophage can swallow up to 100 bacterial cells, eat Old red blood cells, dead neutrophils, parasites, dead tissues... They also play a role in starting the immune process.

Mono white blood cells increase in acute and chronic infections (tuberculosis, influenza, typhoid, fungal, hepatitis, cancer...) in rare cases decrease. Can be seen after cortisone injection.

Lymphocytes (1500 - 3000/mm3)

These are immune cells. There are 2 types: B lymphocytes have a humoral immune function, producing antibodies that circulate in the blood to attack pathogens. T lymphocytes have a cellular immune function. Once stimulated, they become inducible lymphocytes, participating in the destruction of invading agents. Most lymphocytes are in the spleen and lymphatic tissues. The circulating lymphocytes in the blood make up less than 5% of the total number of these cells in the whole body. The increase and decrease of lymphocytes often also change in some viral and bacterial infections (arthritis, hypersensitivity reactions to drugs (phenytoin, p - aminosalicylic acid...). Immunodeficiency can be congenital or acquired (eg, due to chemotherapy used in cancer, immunosuppressive agents used in tissue transplantation, radiation exposure, HIV infection).

Platelets (150,000 - 300,000/mm3)

These are non-nucleated cells involved in the haemostasis process. When the vascular wall is damaged, platelets will gather there until a platelet plug is formed to seal the damaged area. Thrombocytopenia below 100,000/mm3 is easy to cause bleeding. Thrombocytopenia can be caused by bone marrow failure, cancer, arsenic, benzene poisoning, bacterial and viral infections. Many drugs can cause thrombocytopenia (chloramphenicol, quinidine, heparin, many cancer drugs). Many other drugs are capable of inhibiting platelet adhesion (aspirin).