General Instructions and Patient Preparation
One of the most important factors in determining the accuracy and reliability of your lab test is you, THE PATIENT. After all, it is a sample from your body (blood, urine, or some other specimen), on which the test will be performed. Therefore, it is essential that you do the following to ensure that the results will be useful and interpreted correctly by your doctor.
It should be noted that many tests require no special preparation. But for those that do, be certain to adhere to the instructions provided.
1. LIPID PROFILE/LDL SUBFRACTIONS
- The patient should fast overnight for minimum of 12 hours.
- Avoid coffee/Tea and strenuous exercise for at least one day before specimen collection.
- The patient should be maintaining a stable weight and be on normal diet for at least week.
- Wait 4-8 weeks after an episode of myocardial infarction or similar traumatic episode.
- History of hypolipidemic medications, if given, is required for interpretation of results correctly.
- Blood is collected in Red top vacutainer. Serum specimen should be separated within 1 hour of sample collection.
- Note: Grossly haemolysed samples are unacceptable.
- LDL sub fraction is sent to referral laboratory only if required.
2. BLOOD GLUCOSE
- For a fasting blood glucose test, do not eat or drink anything other than water for at least 12 hours before the blood sample is taken. If you have diabetes, your doctor may ask you to wait until you have had your blood collected before taking your morning dose of insulin or diabetes medicine.
- For a 2-hour postprandial test, you need to have your blood collected exactly 2 hours after a regular lunch/Break Fast.
- Random blood Glucose (RBG):No special preparation is required before having a random blood glucose test.
3. Glucose Tolerance Test (Non-Pregnant)
- Patient should be fasting for 8 hours (no food or drink, except for water). A fasting blood specimen will be drawn and tested. You will then be given a glass of glucose drink. Your blood will be drawn once each hour or each half hour after you finish the drink.
The number of hours may vary from 2 to 4.
4. Prenatal Glucose Tolerance Tests
- For the pregnant ladies your physician may order glucose tolerance testing during pregnancy.
- 50 GRAM 1 HOUR GLUCOSE TOLERANCE TEST (GESTATIONAL DIABETES SCREEN)
- No special patient preparation is required.
- This test is done without regard to the time of day or time of last meal. You do not need to fast before this test is given.
- You will be given a glucose drink and your blood will be drawn one hour after you finish the drink.
- Please allow at least 1 ½ hours for this test to be completed.
- 100 GRAM 3 HOUR GLUCOSE TOLERANCE TEST (GESTATIONAL DIABETES)
- This test should be performed in the morning after an overnight fast of at least 8 hours and after at least 3 days of unrestricted diet and activity.
- A blood specimen will be drawn and tested.
- You will then be given a glucose drink.
- Your blood will be drawn once each hour after you finish the drink for three hours.
- This test will be completed in 4 hours. Hence be prepared to spend this time at the lab.
5. Urine For Routine Urinalysis /Culture
- The first morning sample is preferable for urine routine test and mandatory for culture test.
- Obtain a sterile container from the laboratory. Please avoid touching the inside of the container and/or the lid in order to maintain sterility. Obtain a sterile container from the laboratory. Please avoid touching the inside of the container and/or the lid in order to maintain sterility.
- Female: Wash your hands with soap and water. Separate labial folds (thick skin folds), cleanse opening of urethra three times with soap and water. Allow the initial stream of urine to pass, and then collect mid-stream urine into a sterile container.
- Male: Retract foreskin, clean glans three times with soap and water. Allow the initial stream of urine to pass, and then collect urine into a sterile container.
- The specimen should be brought for testing as soon as possible. If there is a delay, the specimen should be refrigerated.
6. 24-HOUR URINE SPECIMENS
- 24 hours urine sample can be requested by your physician for micro albumin, clearance, urine protein, bence jones protein etc. Patients should follow this advice for 24 hrs. urine collection.
- Do not add anything but urine to the 5 liter can/container and do not pour out any liquid or powder that may already be in the collection container.
- The collection container should be kept in cool place during collection period.
- Upon arising in the morning, urinate into the toilet, emptying your bladder completely. Do not collect this sample.
- Collect all urine voided for 24 hours after this time in the container provided. All urine passed during the 24-hour time period (day and night) must be saved. Urine passed during bowel movements must also be collected. Be careful not to contaminate urine specimen with faeces.
- Keep collected urine between all voiding in a cool place.
- At exactly the same time the following morning, void completely again (first time after awakening) and add this sample to
- the collection container. This completes your 24-hour collection.
- Take the 24-hour specimen to the lab as soon as possible.
- Sterile containers and 24 hr urine containers may be picked up at our lab between the hours of 8am to 4pm.
7. Stool Specimen Collections
- STOOL FOR OCCULT BLOOD
- Diet and drugs may affect results of occult blood testing. Please talk to your physician before making any changes in diet or medications prescribed for you.
- You will collect a separate sample from three different stools, usually on consecutive days. Each stool specimen should be collected into a clean container and should not be contaminated with urine or water.
- You may be asked to collect a stool specimen for laboratory testing. You may collect this specimen in a clean leak proof container with a tightly fitting lid provided by the lab.
- Prior to collecting a stool specimen, avoid consuming the following:
- Ant diarrheal Medications
- Oily Laxatives
- Barium or Bismuth
8. Semen Analysis
- Refrain from sexual intercourse or masturbation for 3 days.
- Produce the sample by masturbation without artificial lubricants. Do not use a condom, as condoms contain spermicidal agents.
- Collect the sample into the clean, wide mouth container supplied. It is important that the whole ejaculate is collected. If not, the specimen should be labelled as incomplete.
- Within half an hour of collection, sample should be brought to the laboratory. Keep the specimen warm in a pocket near your body.
- Label the specimen with name, date, and time of the collection.
- Samples may also be produced in a room at the laboratory.
9. Sputum for Culture And Acid Fast Mycobacterium (AFB)
- Patient should rinse mouth and gargle with water immediately prior to collection.
- Collect specimen from deep cough into a sterile container.
- Patient should avoid any contamination with saliva.
- Return specimen as soon as possible (preferably within half an hour of collection). If there is a delay, specimen should be refrigerated.
- Please label the specimen container with patient's name, date and time.
10. Plasma Cortisol Test
- Cortisol may be tested in blood or urine. If blood cortisol levels are requested by your physician, you may be asked to have your blood drawn once (random Cortisol) or multiple times. Your physician will inform you if you are having multiple blood draws for your cortisol testing.
- Cortisol blood tests may be drawn at about 8 am, when cortisol should be at its peak, and again at about 4pm, when the level should have dropped. Sometimes a resting sample will be obtained late in the evening.
- If your physician requests a urine cortisol, you will be asked to collect either a 24-hour urine or a single first morning specimen.
11. Vitamin B12 and Folate
- A fasting specimen (no food or drink, except for water) for 12- 14 hours before blood is drawn is preferable but not mandatory.
- Patient should be fasting (no food or drink, except for water) for 12-14 hours before blood is drawn.
13. Digoxin Level
- Blood should be drawn 6-8 hours after the last dose of digoxin was taken. Mention the time of drug dose.
14. Iron Studies
- No specific preparation required. Age and blood transfusion history if any, should be informed.
15. Apolipoproteins A1/B Test
- 14 hours fasting is required, no liquids except water.
- The patient should strictly avoid theophylline, chocolate, vanilla, banana, alcoholic beverages, Tea/coffee, tobacco and strenuous exercise at least 72hrs before and during specimen collection.
17. Urinary Catecholamine
- The patient should strictly avoid alpha-one blockers, aminophylline, ampicillin, beta-blockers, ephedrine, imipramine, methyldopa, MAO inhibitors, nicotine, phenacetin, phenothiazine, thephylline, vasodilators, aspirin, PAS, alpha-two agonists, bromocriptine, calcium channel blockers (long term use), clofibrate, MAO inhibitors, propranolol, penicillin, reserpine, thyroxine, alpha-methyldopa, isoproterenol, paracetamol, cimetidine, metoclopramide, vigorous exercise, alcoholic beverages, tea/coffee and tobacco at least 72 hours before and during specimen collection.
18. Plasma Catecholamine
- The patient should strictly avoid drugs like aldomet (alpha methyldopa), labetalol, isoproterenol, isoetharine, alpha-one blockers, aminophylline, amphetamines, ampicillin, beta-blockers, ephedrine, imipramine, nicotine, phenacetin, theophylline, phenothiazine, vasodilators (minoxidil, nitrates & hydralazine), aspirin, PAS, alpha-two agonists, bromocriptine, calcium channel blockers (long term use), L-dopa, cimetidine, clofibrate, MAO inhibitors, propranolol, penicillin, reserpine, thyroxine, vigorous exercise, severe stress and cigarette smoking at least 72 hours before and during specimen collection.
19. Urinary Metanephrines
- Patient should strictly avoid alpha-methyldopa, buspirone, codeine, isoproterenol metabolite, mandelamine, L-dopa, paracetamol, metoclopramide, pepper, alcoholic beverages, tea/coffee, tobacco and strenuous exercise at least 72hours before and during specimen collection.
- The patient should strictly avoid banana, kiwis, walnut, avocado, eggplant, pineapple, plum, tomato and drugs including fluorouracil, malphalan, paracetamol, acetaminophen, caffeine, heparin, L-dopa, reserpine, salicylates, chlorpromazine, imipramine, isoniazid, MAO inhibitors, phenothazine, alcoholic beverages, tea/coffee, tobacco and strenuous exercise at least 72hours before and during specimen collection.
21. Benzodiazepines/Tricyclic Antidepressants
- The patient should strictly avoid all benzodiazepines/tricyclic antidepressants other than the drug to be monitored. Also avoid propranolol, prochlorperazine, quinidine, lidocaine, mesoridazine, phenelzine, thiothixene clozapinedesmethyl, brupopion, EDDP, haloperidol, amoxapine, norcyclobezaprine, paroxetine, dothiepin, clozapine, cyclobenzaprine, promazine, triflupromazine, maprotilline, methadone, fluvoxamine, propoxyphene, norfluoxetine, mianserin, setralinedesmethyl, trimipramine, fluoxetine, chlorpromazine, trifluoperazine, sertraline, loxapine, thioridazine, carbamazepine.
22. Stimulation / Suppression Tests
When ordering tests in a timed series (e.g., glucose tolerance test, ACTH stimulation tests etc):
- Label each specimen with the patient's name and time of collection.
- Write the total number of specimen submitted on the test requisition form.
- Submit all specimens within a series, together in one specimen bag.
- Always mention the complete patient demographics (age, sex etc) and phone number.
23. Pre Analytical Variables
When ordering tests in a timed series (e.g., glucose tolerance test, ACTH stimulation tests etc):
- Diurnal variation: It is encountered when testing for hormones, iron, acid phosphatase and urinary excretion of sodium, potassium and phosphate.
- Exercise: Physical activity has transient and long term effects on laboratory determinations.
- Diet: Diet of an individual's diet can greatly affect test results.
- Age: Age of the patient has an effect on serum constituents. Four age groups have been broadly defined namely Newborn, Childhood to puberty, adult and Elderly adult to define the biological reference range.
- Gender: After puberty men have higher levels of Alkaline phosphatase, Aminotransferase, CPK & Aldolase as compared with women. This is due to larger muscle mass of men. Women have lower levels of Magnesium, Calcium, Albumin, Hemoglobin, Iron & Ferritin. Menstrual blood loss contributes to lower iron values.
- Stress: Mental & Physical stress induce the production of ACTH, Cortisol & Catecholamines, HDL cholesterol decreases by as much as 15% while Total Cholesterol increases.
- Posture-During phlebotomy posture of the patient can have effect on various laboratory results. Upright position increases hydrostatic pressure, thereby reducing plasma volume. Parameters affected by postural change are Albumin, total proteins, Enzymes, Bilirubin, Calcium, Cholesterol, Triglycerides & Drugs bound to proteins.
- All patients should be advised to avoid changes in their diet, consumption of alcohol & strenuous exercise 24 hrs prior to phlebotomy.
- Obesity-LDH, Cortisol, Insulin & Glucose increase obesity. Testosterone levels are reduced in obese men.
- Smoking-tobacco smokers have high blood Caboxyhemoglobin, Plasma catecholamines & serum Cortisol. Chronic smoking increases Hemoglobin, RBC, MCV, WBC, Lactate, Insulin, Epinephrine, Growth hormone & urinary 5HIAA. Smoking decreases Vitamin B12, Immunoglobulins, sperm counts & motility.
- Medication: Certain test parameters are affected by drug intake.