ATI Exam Study Guide Diagnostic Lab Tests and Values

Diagnostic Lab Tests and Values Overview ○ ABGs ■ Provideinformationnecessarytomanageapatient'srespiratory(ventilation) and metabolic ( Renal) acid base an electrolyte status ■ Must be sent on Ice to the lab ■ PCO is 35 to 45 ■ HCO3 is 22 to 28 ■ PO2 is 85-100 ■ O2 is 95-100% ○ PH level ■ Inversely proportional to hydrogen ion concentration ■ As hydrogen ion concentration decreases, the pH will increase ○ Alkalosis, the pH is elevated ○ Acidosis, the pH is decreased Bicarbonate measures the metabolic component of the acid base equilibrium, related to kidney and renal function ● ● ● ● ● ● ○ PCO2 is the measurement of ventilation capacity, the faster and more deeplywant to breathe is, the more CO2 that is blown off ○ O2 saturation is an indication of percentage of hemoglobin in the oxygen ■ Tissues are well perfused when the numbers read 92% to 100% ■ Determine this by using pulse oximeter ELISA ○ Test for antibodies to HIV in serum or plasma ○ Most widely used serologic test for AIDS Western blot ○ Done if the Elisa is inconclusive, this one is highly predictive of HIV infection Cardiac catheterization ○ Done to visualize the heart chambers, arteries, and great vessels ○ After the procedure, patients should stay on bed rest for 4-8 hours ○ Assess the pulses in both extremities, watch for bleeding, hematoma, and possible absence of a pulse Direct Coombs test ○ Demonstrates if the patient’s RBCs have been attacked by antibodies againstthem, usually seen with Rh negative mothers Indirect Coombs test ○ Detect circulatory antibodies against RBCs CPK, Ck-MB, CP serum tests ○ Used to detect muscle injury ○ CPK is usually found in the heart muscle, skeletal muscle, and brain, and are elevated when an injury occurs to these cells ○ CK-MB isoenzyme levels are helpful in quantifying the degree of myocardial infarction ● Serum creatinine test and BUN ○ Used to diagnose impaired renal function ○ Elevated results indicate renal injury or disease ● Creatinine clearance ○ A measure of glomerular filtration rate ○ The ability of the glomeruli to act as a filter is decreased by diseases such as glomerulonephritis, acute tubular necrosis, and other primary renal diseases ○ Requires a 24-hour urine collection and a serum creatinine level as well ● Glucose tolerance test ○ Evaluate patient's ability to tolerate a standard oral glucose load ○ Evaluated by obtaining serum and urine specimen for glucose determinations before glucose Administration, as well as at 30 minutes, 1 Hour, 2 hours, and 4 hours after ○ Fasting should be 70-115 ○ 30 min - <200 ○ 1 hour- <200 ○ 2 hours- <140 ○ 3 hours- 70-115 ● Glycosylated hemoglobin (HBA1C) ○ Used to monitor diabetes treatment and measures the amount of glucose in the blood over the course of 100 to 120 days ● Barium enema ○ Series of X-ray films that visualize the colon ○ May be used to diagnose incorrect intussusception in children ● Cholesterol ○ Should be <200 ● Hemoglobin ○ A measure of thetotalamountofhemoglobinintheperipheralblood,reflectingthe number of red blood cells in the blood ○ Decreased amount indicates anemia ● Hematocrit ○ Percentage of red blood cells in the total volume of blood ○ Decreased amount indicate anemia ● Holter monitoring ○ Continuous recording of electrical activity of the Heart by using ECG that records during unrestricted activity, rest, and sleep ● Intravenous pyelography ○ X-ray study that uses radiopaque contrastdyetovisualizethekidneys,renalpelvis, ureters, and bladder ● MRI ○ Contraindicated in obese patients, confused and agitated patients, unstable patients that require continuous life support equipment, and those with implantable metal objects ● Pap smear ○ Used to detect neoplastic cells in a cervical and vaginal secretions ○ Should be performed yearly and women who are over 18 amd sexially active ● Paracentesis ○ Have the patient urinate and empty the bladder ○ Position the patient in a high Fowler position with the feet supported ● Partial thromboplastin (PTT) ○ Assesses the intrinsic system and common pathway of clot formation ○ Used to assess patients onheparin,theirlevelswillbeonetotwotimeshigherthan normal ○ Normal level is 60- 70 seconds ● Prothrombin time (PT) ○ Evaluate the extrinsic system and common pathway in a clotting mechanism ○ Used to assess patients on warfarin, their levels will be one to two times the normal range ○ Normal level is 11 to 12.5 seconds ● Platelet count ○ Actual count of the number of platelets per cubic millimeter of blood ○ Normal level is 150-400,000 ● BUN ○ Blood urea nitrogen, directly related to the metabolic function of the liver and excretory function of the kidneys ○ Those with elevated levels may have renal disease or injury, as well as azotemia ● HCG ○ Blood test  or urine test to detect HCG in the blood of a woman who might be pregnant ○ These levels will appear as early as 10 days after conception ● Uric acid ○ Nitrogenous compounds that is a product of purine catabolism ○ When levels are elevated, the patient may have gout 