Topic 6 Flashcards
– This refers to as highly complex mixture of cells, enzymes, proteins and inorganic substances. It is the red fluid of the blood vessels. Blood is opaque. On treatment with either, water or other reagents becomes transparent and assumes lake color. It is faintly alkaline. Normal pH is 7.35 to 7.45. cts.
Blood
– aka capillary blood, bright red in color and which is oxygenated blood.
Arterial Blood
– dark red in color, contains increased amount of carbon dioxide and which is non-oxygenated blood.
Venous Blood
– found in Nitrates and Nitrites poisoning which is chocolate brown in color.
Methemoglobin (Hbm)
– found in the presence of bacteria (clostridium perfringens) in severe constipation, enterogenous cyanosis and blood is lavender is color.
Sulfhemoglobin (HbS)
is responsible for red color, normal Pilipino has 200cc, 6 glasses means loss of life, 3 glasses will cause anemia. Hemoglobin is responsible for red color of blood which contains iron protein called globin (protein) and hematin (organic compound of iron). 14-17 grams of hemoglobin is present for each 100 cc of blood for adult.
Hemoglobin
– Skin/Finger/Ring Puncture, arterial blood and small quantity of blood. Puncture sites are;
Ring finger (Adult and Children)
Ear lobes (Adults)
Heal or Toe (Infants and Children) – use of lancet or pricker
Capillary Blood Sample
– Larger volumes of blood and blood taken from the vein
Cephalic Vein
Medial Cephalic Vein
Basilic Vein
Jugular Vein
Venous Blood Sample
– Larger volumes of blood and blood taken from the arteries
Radial Artery
Brachial Artery
Femoral Artery
Carotid Artery
Arterial Blood Sample (Venipuncture Method)
– an extremely sensitive test that can be applied to minute stain. For many years the most commonly used preliminary test for blood. Its use has generally been discontinued, as it is known carcinogen. A very delicate test and will detect blood when present in dilution of 1:300,000 parts. The Benzidine test never fails to detect blood even when very old, decomposed stain with all sorts of contamination is examined.
Benzidine Test
This test is more sensitive than guaiacum test and is valuable as a negative result. If the stain reacts negatively it is not blood. The positive result is only indicative that blood may be present.
Benzidine Test
(a small amount of powdered Benzidine dissolved in glacial acetic acid)
Benzidine solution
Positive Result: Intense blue color produced immediately.
Benzidine test
Limitation of the Test: is not specific test for blood. Positive result may be obtained from the substances as sputum, pus, nasal secretion, plant juices, formalin, clay and gum. The reaction is weaker and produces faint coloration.
Benzidine test
– An alternative test to Benzidine test. It can detect blood in a dilution of 1:80,000,000 parts. A positive result with this test is highly indicative of blood. The negative result is therefore valuable and is conclusive as to the absence of blood.
Phenolphthalein Test
(1 to 2 grams of phenolphthalein to 100 ml of a 25% potassium hydroxide in water added with one gram of zinc powder heated until colorless).
Phenolphthalein solution
Positive Result: Rose color develops/deep pink/permanganate color.
Phenolphthalein test
Limitation of the Test: The test will also give positive result to copper salts, potatoes and horseradish.
Phenolphthalein test
– A fairly delicate test showing the presence of fresh blood in a solution of 1:50,000 dilutions. It may not react to very old stain.
Guaiacum Test
Positive Result: Beautiful blue color that appears immediately.
Guaiacum Test
Limitation of the Test: The test also reacts with saliva, pus, bile, milk, rust, iron, salts, cheese, glutten, potatoes, perspirations and other oxidizing substances.
Guaiacum Test
– This test is not as sensitive as the benzidine test.
Leucomalachite Green Test
(1 gram leucomalachite green dissolved in 48 ml glacial acetic acid and diluted to 250 ml water).
Leucomalachite green solution
Positive Result: Malachite green or bluish green
Leucomalachite Green Test
– An important presumptive identification for blood. The reaction of luminal with blood results in the production of light rather than color. By spraying luminal reagent onto a suspected item, large areas can be quickly screened for the presence of bloodstains.
Luminol Test
Positive Result: Luminescence or emission of light.
Luminol Test
– This refers to an enzyme that accelerates the oxidation of several classes of organic compounds by peroxide.
Peroxidase
The actual proof that a stain is blood consists of establishing the presence of the characteristic of blood pigment hemoglobin or one of its derivatives. Hemoglobin is the red coloring matter of the red blood cells of the blood.
The Confirmatory Test for Blood
– Microscopic test is useful for the demonstration and mensuration of blood corpuscles for making the distinction between mammalian, avian, piscine and reptilian blood for the investigation of menstrual, lochial and nasal charges.
Microscopic Test for Blood
– The smear is flooded with the stain and allowed to stand for a minute. Distilled water is added until a metallic scum forms on the surface. Let stand for 3 minutes, wash with water and dry.
Wright’s Stain
– circular, biconcave discs with nucleus. Appear as characteristics non – nucleated discs. Exception is camel and closely related animal as llama whose red blood cells are oval but also without nucleus.
Mammalian red blood cells
– larges, oval and nucleated.
Birds, fish and reptile red blood cells
– larger than mammals, oval and nucleated.
Amphibian red blood cells
– circular and nucleated.
Lamprey eel red blood cells
– The identification of blood can be made more specific if microchemical or microcrystalline test is applied or performed. Takayama test and Teicmann test are the most popular ones.
Microchemical Test and Microcrystalline Test for Blood
– The test depends on the addition of the specific chemicals to the blood so that characteristics crystals with hemoglobin will be formed.
The Teicmann Test
Positive Result: Dark brown rhombic crystal of haemin or haematin chloride arranged singly or in cluster.
Microchemical Test and Microcrystalline Test for Blood
Limitation of the Test: The test will also give positive results for indigo – dyed fabrics. If the stain is old or washed or is changed by chemical reagents, the crystals are not formed. The addition of too much salt or presence or moisture in the acid or over – heating of the slide may result in failure.
Microchemical Test and Microcrystalline Test for Blood
– The test depends on the addition of specific chemicals to the blood so that characteristic crystal with hemoglobin will be formed.
Acetone – Haemin Test
Procedure: Place dried stain on glass slide and cover with cover slip with a needle interposed to prevent direct contact of the cover slip with the slide. Add a drop of acetone then a drop of acetic acid.
Acetone – Haemin Test
Positive Result: Small dark, Diachronic Acicular Crystals of Acetone Haemin
Acetone – Haemin Test
– A delicate test for the presence of hemoglobin. The test depends on the addition of specific chemicals to the blood so that characteristic crystals of hemoglobin derivatives will be formed.
Haemochromogen Crystal Test of the Takayama Test
– The most delicate and reliable test for the determination of the presence of blood in both old and recent stains. This test is performed by means of an optical instrument known as Spectroscope, an optical instrument for forming and examining spectra.
Spectroscope Test for Blood
Procedure: Dissolved bloodstain in water or saline solution. Place in small chamber (glass) with parallel sides so arranged that the rays of light will pass directly through it. The chamber is placed in the spectroscope and the instrument is so adjusted that the spectrum is clearly visible.
Haemochromogen Crystal Test of the Takayama Test
Positive Result: Upon absorbing some of the rays from the spectrum, it produced characteristic dark colored bands, which vary with the type of blood pigment.
Haemochromogen Crystal Test of the Takayama Test
is the standard test used to determine whether the stain/blood is of human or animal origin. The precipitin test is very sensitive and requires only a small amount of blood for testing.
Precipitin Test for Blood
Human bloodstain dried for as long as 10 to 15 years and longer may still give a positive precipitin reaction. Even extracts of tissues from mummies four to five years old have given positive reaction with the test. Experience has shown that human bloodstain diluted by washing in water and left with only a faint color may still yield a positive precipitin reaction.
Precipitin Test for Blood
Reagent: Precipitin/Antiserum
Procedure: Scrape off bloodstain if on hard material. Powder the scraping and extract with saline solution. If the stain is cloth, paper or similar material, cut a small portion and the place in a test tube and add extract with saline solution. Allow mixture to stand overnight and centrifuge to clean the solution. Dilute with saline solution. Layer an extract of the bloodstain on top of the human antiserum/precipitin in a capillary tube.
Precipitin Test for Blood
Positive Result:
Development of a white cloudy line at the contact point of the fluids that appears immediately or within one or two minutes.
Human blood, or for that matter, any protein of human origin in the extract will react specifically with anti – bodies present in the serum as shown by the formation of cloudy ring or band at the interface of the two liquids. Principle Involved in the Precipitin Test: When a rabbit is injected a human blood serum or whole human blood, the precipitin that develops in its serum will react with the protein of human blood serum, other human body fluids and other human proteins or any other protein as human origin.
Precipitin Test for Blood
Limitation of the Test: The precipitin reacts not only with blood proteins but also with other body proteins as those on saliva, semen, mucus and other body fluids.
Precipitin Test for Blood
– This refers to any of the complex chemical units in the chromosomes by which heredity characters are transmitted that occur in pair that is a factor occurring singly in a garmete. There are two genes or factors called gene A and gene B, These are found in the chromosomes. Since chromosomes go on pair, each of which carries or fails to carry one of these genes and an individual’s genetic constitution may be represented by AA, AB, BB, BO, AO, OO which are called genotypes, where O represents the absence in the chromosomes of either the A or B gene that is responsible for the transmission of hereditary characteristics.
Gene
– This refers to any of the microscopic rod – shaped bodies bearing genes responsible for the transmission of hereditary characteristics are observed to occur in pairs.
Chromosomes
– This refers to term used to denote the expression of the inherited characteristics as found in the individual that is actually the blood groups.
Phenotypes
– This refers to paired genes. It is either homozygous or heterozygous.
Genotype
– This refers to paired genes that are similar.
Homozygous genotype or pure genotype
– This refers to paired genes that are dissimilar or not alike.
Heterozygous genotype or hybrid
– This refers to sexual cells; reproductive cell that unites with one another to from cell that develops into a new individuals.
Gamete
– This refers to male sexual cell.
Sperm cell or microgamete
– This refers to female sexual cell.
Egg cell or macrogamete
– This refers to pair of genes occurring in a gamete produced during fertilization. The cell formed by the union of an ovum and sperm.
Zygote
– This refers to pairs or contrasting genes, which determines the expression of the inherited characteristics of an individual.
Alleles