Name: Teng Cassandrea
Laboratory: Biochemistry

Neonatal serum bilirubin

o Breakdown of hemoglobin>>globin + heme
o Globin + iron >>re-utilized, leaving porphyrin portion of heme
o Breakdown of heme occurs in reticuloendothelial system
o Porphyrin ring opened up to form biliverdin
o Biliverdin>>reduced to bilirubin
o Bilirubin>>transported in plasma to liver>> conjugated with glucuronic acid
o Conjugated bilirubin>>further broken down in the intestines by intestinal bacteria>>urobilinogen
o Various reduction products of bilirubin may be absorbed from intestine>>returned to liver for re-excretion
o Any overload or blockage of this system raises levels of plasma total bilirubin

At least 80% of plasma bilirubin is unconjugated or indirect. When bilirubin in the blood is excessive, it deposits in the tissues, which causes jaundice. It may be caused by:
o Production of bilirubin more than the normal liver can excrete (e.g. hemolytic disease).
o Failure of the damaged liver to excrete the bilirubin produced in normal amounts (e.g. hepatitis).
o Obstruction of the excretory ducts in liver.

Neonatal physiological jaundice is common in newborns due to an immature fetal liver. The liver cannot conjugate all the bilirubin produced because of deficient enzymes. This jaundice however, disappears as the liver matures and enzymes function improves.

Upon receiving the patient samples, the samples are spun down so that the serum can be obtained for an accurate reading. The samples are that loaded into the REICHERT UNISTAT Bilirubinometer using a curvette. The readings are the recorded onto the request form and left to be verified.

G6PD screening test

o G6PD>>key enzyme in hexose monophosphate pathwayàrequired for formation of NADPH.
o NADPH>>essential for maintaining integrity of erythrocyte membrane
o G6PD deficiency may be the cause of hemolytic disease of newborn
o Drug-induced hemolytic anemia is most commonly associated with erythrocyte deficiency of G6PD.
o Deficiency is due to presence of G6PD enzyme that is present in young cells but rapidly disappears with cell aging.
o Disease is transmitted as an X-linked recessive.
o Full-expression occurs also in females who are homozygous for the gene; intermediate expression occurs in the heterozygous female carrier
o Fluorescent spot test is used to screen for G6PD deficiency
o NADPH produced in the reaction fluoresces under long-wave UV-light
o If there is a marked deficiency of G6PD or if this enzyme is lacking entirely, no fluorescence will be observed.

Samples for G6PD screening are usually cord blood for routine screening of newborn. The samples should always be received in EDTA tubes to prevent blood from clotting. Four types of control are used for this test; intermediate, blank, deficient and positive. The positive control is taken from the patient sample and is changed everyday. First, 100 microlitres of buffer is aliquoted into labeled tubes. This is followed by 5 microlitres of the patient’s blood. It is mixed left to incubate for 10 minutes. After the incubation, the samples are placed on filter paper and left to incubate for another 10 minutes. Over-incubating will cause false results; hence a timer must always be set. The filter paper is then read under the UV-light.

If the results are weak or negative, the test must be repeated and the sample must be checked for blood clots. If the blood is clotted, the nurse must be contacted to take a fresh sample of blood in an EDTA tube.

Urine FEME

o Kidneys maintain the internal environment by selectively excreting or retaining various substances accordingly to specific body needs
o They consist of a number of smaller functional units>>urinary tubules or nephrons
o Nephrons open to large collecting ducts, which open into a ureter.
o The two ureters run backward to open into a urinary bladder
o One of the main functions of the kidneys is the removal of waste products such as urea, uric acid, and creatinine from the body
o They also regulate volume and composition of body fluids and maintain correct osmolality, ion concentrations, and acid-base status of body
o First step in the production of urine is filtration of plasma passing through kidneys.
o Filtration occurs from glomerular capillaries into Bowman's capsule to form tubular fluid
o Glomerular filter prevents plasma proteins from passing into nephrons, but is permeable to all other plasma constituents (such as ions, glucose, amino acids, urea, etc)
o Thus filtration in the kidney is essentially non-selective — substances, which the body needs to retain, are filtered, as well as those substances, which need to be excreted.
o Urine analyzed to detect body disturbances>>endocrine or metabolic abnormalities, in which kidneys function normally but excrete abnormal amounts of abnormal amounts of metabolic end products specific for a particular disease.
o Analysis is also done to detect for intrinsic conditions that may adversely affect kidneys or urinary tract.
o Diseased kidneys cannot function normally in regulating volume and composition of body fluids, and in maintaining body homeostasis
o Consequently, substances normally retained by kidney or excreted in small amounts may appear in urine in large quantities, or substances normally excreted may be retained.
o Structural elementsàRBCs, WBCs, epithelial cells from urinary tract, and cast from diseased kidneys may appear in the urine
o Crystals, bacteria, yeast, protein, nitrite, glucose, ketone bodies, urobilinogen and bilirubin can also be found in the urine
o Different types of crystals:
§ pH<7 Amorphous nitrate
§ pH>or= 7 Amorphous phosphate
§ Calcium oxalate
§ Uric acid
§ Triple phosphates
§ Ammonium nitrate
§ Di-calcium phosphate
§ Calcium carbonateCalcium sulphate