Part 1 Flashcards
Measures reduction in light transmission by PARTICLES IN SUSPENSION
Turbidimetry
Similar to turbidimetry, but light is measured AT AN ANGLE FROM LIGHT SOURCE
Nephelometry
Chemical rxn produces colored subs that absorbs light of a specific wL
Amt of light absorbed = analyte concen’n
SPECTROPHOTOMETRY
Measures light absorbed by GROUND STATE ATOMS
AAS
Atomic absorption spectrophotometry
Atoms absorb light of SPECIFIC wL and emit light of longer wL (lower energy)
Fluorometry
Chemical rxn that produces light
Involves oxidation of (3)
Chemiluminiscence;
- Luminol.
- Acridinium esters
- Dioxetanes
Critical component of all spectrophotometers
Device use to select the appropriate wL
Monochromator/wL selector
Types of wavelength selector (4)
- Filter
- Prism
- Grating monochromator
- Holographic gratings
Atoms absorb energy at a particular wL
Excitation
In fluorescence, electrons release energy as they return to ground state by:
EMITTING LIGHT ENERGY OF A LONGER WAVELENGTH AND LOWER ENERGY THAN THE EXCITING WL
(⬆️ Wavelength = ⬇️ energy)
Fasting samples (5) At least 8hours
FLIGhT Fbs Lipid panel Insulin Gastrin TAG
Tests that needs CHILLING
-slurry of crushed ice and water - ice cubes alone will lyse RBC
A3 G2 L P2 R ACTH, ammonia, Acetone Gastrin, Glucagon Lactic acid Pyruvate, PTH Renin
TestS that need WARMING (2)
37’ heat block
Heel warmer
Hold in hand
Cryoglobulins
Cold agglutinins
Protection from light (5)
- aluminum foil
BCEV2
Bilirubin
Carotene
Erythrocyte protoporphyrin
Vit A, Vit B12
Requires CHAIN OF CUSTODY (3)
- lockbox may be required
Blood alcohol
Drug screens
DNA analysis
Increased upon PUMPING FIST DURING VENIPUNCTURE
PLaCK ⬆️
Phosphorus
LActic acid
Calcium
K+
DECREASED upon PUMPING FIST DURING VENIPUNCTURE
⬇️ pH (acidic)
TOURNIQUET > 1 min (⬆️)
K+
Lactic acid
Total proteins
Hemolysis causes ⬆️ in (7)
KLAMP I K+ LD Ammonia, Ast Mg Phosphorus Iron
Tube for LEAD DETERMINATIONS
Tan top (EDTA)
Tan Hemogard closure tubes
inversions: 8 times
Lead content of Tan Top tube
Less than 0.1 ug/mL lead
K2 EDTA
Measured every 3-6 months to monitor glycemic control
Hba1c
Decreased GLYCOSYLATED HB (HBA1C)
- Shortened RBC survival
- Lower mean RBC age:
- hemolysis, recovery fr. acute blood loss, transfusions or splenectomy
Used to assess short-term (3-6weeks) glycemic control
Fructosamine
- average half life of proteins is 2-3weeks
Most common method of urea assay couples urease with:
GLDH
glutamate dehydrogenase
Rate of disappearance of nicotinamide adenine dinucleotide (reduced, NADH) at __nm
340 nm
Anticoagulant that will interfere with mtds using urease
fluoride (gray top)
- it inhibits the urease rxn
Effect of cephalosporins when Jaffe rxn is used
Falsely increased
- jaffe mtd is subj to interference by a-keto acids and cephalosporin
Used to determine prognosis
Blood ammonia
- correlation between HEPATIC ENCEPHALOPATHY & Plasma ammonia is not always consistent
Better than blood ammonia as indicator of the severity of disease
Arterial ammonia
Gold standard for Acute Coronary Syndrome (MI)
Cardiac troponins (cTNI, cTNT)
Proteolytic fragments of collagen I formed during bone resorption (turnover)
Cross linked C-Telopeptide (CTXS)
Biochemical marker for bone resorption and can be detected in serum and urine
CTX
New test for the diagnosis and prediction if IMPENDING PRETERM DELIVERY
Fetal Fibronectin (fFN)
Increased after meal consumption
TAG (carried by chylomicrons and chylomicron remnant)
POSTPRANDIAL LIPEMIA
3-STEP PROCEDURE FOR HDL-c MEASUREMENT
- Ultracentrifugation - remove VLDL
- Heparin manganese Pptn - remove LDL
- Analysis of supernatant cholesterol (ABELL-KENDALL ASSAY)
Reference method for measuring cholesterol
GC-MS
- specific; does not measure related sterols
Show great selectivity for K+
VALINOMYCIN MEMBRANES
- used as ion selective carrier
Sodium level in SIADH
Decreased
Hypoosmolar Hyponatremia
Characterized by a euvolemic Hypoosmolar, Hyponatremia associated with HYPEROSMOLAR URINE (result of continued inappropriate natriuresis)
SIADH SECRETION
Due to HYPERPROTENEMIA and HYPERLIPIDEMIA results from the dilution of sample
Pseudohyponatremia
Measurement of sodium with Flame photometer and ISE method (indirect) always result in this type of error because sample is always diluted
Pseudohyponatremia
Accompanied by normal plasma osmolality because of the accumulation of some abnormal osmols or abnormal concentrations of non-sodium osmols
TRUE HYPONATREMIA
Non-sodium osmols (3)
Alcohol
Urea
Glucose
Effect of acute hyperglycemia to sodium
HYPONATREMIA
- result of water shift from the cell
Serum sodium decreases by __ mmol/L every 100 mg/dL rise in serum glucose
1.6
Electrolyte involved in: Blood coagulation Enzyme activity Excitability or skeletal and cardiac mse Maintenance of BP
Calcium
Causes HYPERCALCEMIA (6)
“CHIMPS”
Cancer Hyperthyroidism Iatrogenic causes Multiple myeloma hyperParathyroidism Sarcoidosis
Causes HYPOCALCEMIA (5)
“CHARD”
Calcitonin Hypoparathyroidism Alkalosis Renal failure Vit D deficiency
⬆️ iCa
⬆️ PTH
Parathyroid glands (adenoma, carcinoma)
⬆️ Ica
⬇️ PTH
CHIMS
Cancer Hyperthyroidism Iatrogenic causes Multiple myeloma Sarcoidosis
Formula for TIBC
TIBC = UIBC + SERUM IRON
Formula for TRANSFERRIN SATURATION
Transferrin saturation (%) = Serum iron/tibc x 100
Essential cofactor of more than 300 enzymes
Magnesium
Influence on the activity of more than 300 enzymes
Zinc
Are amphoteric and show DECREASED ABSORPTION when take with foods or medications containing: Calcium Aluminum Mg Iron
TETRACYCLINES
Source of ALP which is heat labile
Bone (90% inhibited by heat and urea)
Source of ALP which is most Heat stable
Placenta
Order of anodal migration of ALP source of enzyme
Liver
Bone
Placenta/Regan
Intestine
ALP enzymes most inhibited by L-phenylalanine
Placenta and Regan (Carcinoma) -80%
Reference method for measuring ALP
Bowers-mccomb
Substrate: p-nitrophenylphosphate
Method for measuring Total ACP activity which is MORE SPECIFIC FOR PROSTATIC FORM
Roy
Roy method for ACP substrate
Thymolphthalein monosphosphate
Increased amylase
Acute pancreatitis
Mumps
Lab dx of acute pancreatitis
Elevation of serum and urine amylase
⬆️ serum lipase
Amylase: elevation, peak and return to normal level
ELEVATION: 2-12 hrs of an attack
PEAK: 24 Hrs
NORMALIZE: 3-5 DAYS
Lipase
PEAK AND HOW LONG IS IT ELEVATED
12-24hrs and REMAINS ELEVATED LONGER THAN AMS
Causes of INCREASED AMYLASE (6)
Mumps Cholecystitis Hepatitis Cirrhosis Ruptured ectopic pregnancy Macroamylasemia
Benign condition in which AMS binds to an Ig molecule.
Chronic ⬆️ serum AMS, but NORMAL urine AMS
Macroamylasemia
Suppress or inhibit serum AMS activity
TRIGLYCERIDES
Ph electrode immersed in a bicarbonate solution used for measuring the partial pressure of CO2 (pco2) in blood
PCO2 electrode
Change in pH because of INCREASE carbonic acid in the electrolyte surrounding the electrodes
Measurement of CO2 in blood by means of pco2
Calibration of blood gas analyzer
2 buffers with known pH and constant Temperature
Why does blood gas analyzer use 2 different standard buffers
To calibrate the ISEs for measuring pH
Measurement of pH is temperature-sensitive procedure, so its is impt that analyzer be maintained at___ on the heat block
37’ +_ 0.05’C
Method used to measure PHEOCHROMOCYTOMA
24-HR URINARY METANEPHRINE
- 95% sensitive and is the best single test
Tumor marker for BREAST, OVARIAN AND GIT
Her-2/neu
Methods used to measure Her2/neu
IHC
FISH
ELISA
Increased PSA (4)
Prostate cancer
Acute/chronic prostate inflammation
Benign prostate hypertrophy
Transurethral prostate resection or biopsy
Reference value of PSA
0-4 ng/mL
Indication of rising PSA level after surgery
Recurring malignancy
