Poct

• Special collection procedures - non-routine laboratory test that may not only involve additional preparation and procedure but may require other specimen such as urine or feces. These can be applied for special cases such as blood donation.
• test: blood type and screen - purpose: blood type and rh factor - special equip: none
• cross match test - purpose: compability of blood - special equip: serum/plasma, donor's rbc
• blood culture - determines infection - blood culture must be 20-30ml per culture, min 10ml for patients with more than 80 pounds, infants 1-4% of total blood volume
• coagulation test - blood clotting function - inverting anticoagulants tubes 3/4 times
• 2-hour postprandial glucose - screening for diabetes, metabolic disorder = 2 hrs after meal
• glucose tolerance test GTT, oral GTT - problems in carbohydrate metabolism - 1 hour for gestational diabetes, 3 hours for other glucose metabolism evaluation
• lactose tolerance test - determines lack of mucosal lactase - same as 2-hr GGT
• paternity/percentage testing - probability that the patient fathered a particular child - chain of custody protocols
• therapeutic drug monitoring - proper drug usage - peak and trough level
• therapeutic phlebotomy- treatment to polycythemia - withdrawal of 500ml blood
• toxicology test - check presence of toxins - usually exist in small amounts
• trace elements - presence of aluminum, arsenic, copper,lead, iron, zinc - meaasured in small amounts
• Blood banks can use special identification systems - ID bracelet (self-carbon adhesive for specimen), Blood ID band (linear bar-code), and Siemens Patient Identification check-blood administration
• typing the blood for transfusion - The blood type (ABO) and Rh factor (+ or -)
• Blood donors should be 17 to 66 years of age, with a minimum weight of 110 lbs.
• Apheresis is the procedure to collect blood components and returning the unwanted blood components back to the patient
• autologous donation - patient donates blood for his use especially for elective surgeries.
• cell salvaging - blood of the patient is salvaged (during surgical procedure), washed and re-infused after testing for residual free hemoglobin.
• blood culture - test that checks the blood for pathogens for patients who have a fever of unknown origin (FUO).
• bacteremia or presence of microorganism and toxins in the blood that causes septicemia, a potentially life-threatening situation.
• ✔For optimum results, the collection  should have 2-4 blood culture sets placed in special bottles, one aerobic (with air) and one anaerobic (without air), that were drawn 30 to 60 minutes apart. 
• ✔Skin antisepsis is crucial in the blood collection procedure because it prevents the contamination by microbial flora in the skin which can be introduced in blood culture bottles and affect the results. 
• three ways to inoculate the medium:

  (1)directly into the bottle (during collection),

  (2)collected in a syringe (after collection), and

  (3)through an intermediate collection tube (in the laboratory).
• COAGULATION SPECIMEN AND ITS PROPER COLLECTION - prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin time (TT) which is a close approximation of the hemostatic system.
• ✔If only the coagulation specimen is drawn, draw a "clear" tube with 1-2 mL which is discarded prior to collection. The blood specimen is then collected using a light blue top with 3.2% citrate tube with the correct (9:1) blood to anticoagulant ratio.
• To ensure proper mixing, invert the tubes gently 3 to 4 times
• Coagulation sample is collected second when an evacuated tube system is used
• The concentration of the sodium citrate should be adjusted for patients with above 55% hematocritt values
• Should the specimen be unable to reach the laboratory within four hours, it should be centrifuged and the plasma frozen.
• 2-HOUR POSTPRANDRIAL GLUCOSE - if the patient is suffering from diabetes and other metabolic problems. - 2-hour PP test is also used to monitor insulin therapy -
• principles of 2-hour PP specimen collection are:

  1.A high-carbohydrate diet was introduced 2 to 3 days earlier.

  2.The patient should fast at least 10 hours prior to the test.

  3.Fasting glucose specimen maybe be collected before the start of the procedure.

  4.A special breakfast containing an equivalent of 100g glucose or a glucose beverage will be given on the day of the test.

  5.Blood glucose specimen will then be collected 2 hours after the meal.
• GTT Procedure

    Before the procedure the patient must eat balanced meal containing approximately 150 grams of carbohydrates for 3 days and must fast for 12 to 16 hours before the scheduled test. Drinking water is allowed to avoid dehydration and because urine specimen is also collected as part of the test.
• 1.The fasting specimen is drawn and the glucose level is checked and should be over 200 mg/dL for the test to proceed.
• The patient is given the glucose beverage dose. Adult dose is 75g while children are given 1g per kilogram of weight. For gestational diabetes the dose should be between 50 to 75g
• 1.If the patient is lactose intolerant, the result will yield a "flat" curve where glucose levels just slightly rise over the fasting level.
• 1.Patients with slow gastric emptying, Crohn's disease and cystic fibrosis could show false-positive results.
• ✔Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) are two other methods used today although the older techniques still exist.
• principles of DNA paternity testing

  1.All involved parties need to submit a government issued photo identification along with the completed Chain of Custody form. The photos of all tested parties are also taken.

  2.The Buccal samples as collected by using a swab that was rubbed inside the cheek and the loose cheek cells adhere to the swab.

  3.Sealed and tamper-evident package are used to hold the specimen during transportation to the laboratory.

  The test results are ready after 48 hours which are usually sent via mail. 
• forensic toxicology (legal consequences of toxin exposure