Specimen Preparation Procedures

Immediate processing of the patient specimen ensures the most accurate laboratory results. Please follow these procedures for preparing and submitting specimens to Main Line Health Laboratories (MLHL).

Blood specimens

Centrifugation is required for blood tests when serum is the recommended specimen. In most cases, serum separator tubes (SSTs) should be used when serum is the preferred specimen. SSTs cannot be used for therapeutic drug monitoring or toxicology studies. Consult the specific test requested in the Directory of Services to ensure the correct blood collection tube is used.

Centrifugation

During specimen processing you may be required to centrifuge the specimen. Centrifugation is required to obtain either serum or plasma specimens. SSTs require centrifugation to allow formation of the gel barrier between the serum and the red cells. Proper centrifugation is critical to proper processing. Directions for the centrifugation steps are included in each specific processing procedure.

SST collection tubes

  1. Perform a routine venipuncture.
  2. Collect approximately 10 ml of whole blood using an SST for each 5 ml of serum required.
  3. Label each patient's specimen with the patient's full name exactly as it appears on the test requisition.
  4. Invert each collection tube gently after collection.
  5. Do not remove the collection tube stopper at any time. Allow the collection tubes to stand for 30 minutes prior to processing. This ensures good clotting of the specimens.
  6. Centrifuge specimens for 15 minutes in the MLHL-provided centrifuge.
  7. Package specimens as directed in the Directory of Services.

Standard non-gel collection tubes

  1. Perform a routine venipuncture.
  2. Collect approximately 10 ml of whole blood using a standard red top blood collection tube (no additives) for each 5 ml of serum required.
  3. Label each patient's specimen with the patient's full name exactly as it appears on the test requisition.
  4. Invert each collection tube gently after collection.
  5. Do not remove the collection tube stopper at any time. Allow the collection tubes to stand for 30 minutes prior to processing. This ensures good clotting of the specimens.
  6. Centrifuge the specimens for 15 minutes in the MLHL-provided centrifuge.
  7. Transfer the clear serum to a clean plastic vial and label with the patient's full name exactly as it appears on the test requisition. Be careful not to transfer any red cells to the transfer vial.
  8. Package specimens as directed in the Directory of Services.

Routine coagulation testing

  1. Perform a routine venipuncture.
  2. Discard the first 5 ml of blood drawn. If drawn from an indwelling catheter, discard the first 20 ml of blood.
  3. Use a blue top blood collection tube containing 3.2 percent sodium citrate. This is the only acceptable sample type. The collection tube must be completely filled. This ensures that the proper ratio of blood to anticoagulant is achieved.
  4. Label each patient's specimen with the patient's full name exactly as it appears on the test requisition.
  5. Invert each collection tube gently after collection.
  6. Do not centrifuge or open the blood collection tube.
  7. Store specimen at room temperature.
  8. Package specimens as directed in the Directory of Services.

Special coagulation testing

Contact the MLHL Client Service Center at 484.580.4200 for detailed instructions. Please consult the specific test requested in the Directory of Services for pertinent information, collection requirements and scheduling information.

Frozen plasma

  1. Perform a routine venipuncture.
  2. Discard the first 5 ml of blood drawn. If drawn from an indwelling catheter, discard the first 20 ml of blood.
  3. Use the blood collection tube identified in the Directory of Services. The collection tube must be completely filled. This ensures that the proper ratio of blood to anticoagulant is achieved.
  4. Label each patient's specimen with the patient's full name exactly as it appears on the test requisition.
  5. Invert each collection tube gently after collection.
  6. Process the specimen as soon as possible after specimen collection. Specimens should be centrifuged for 15 minutes in the MLHL-provided centrifuge.
  7. Transfer the clear plasma to a clean plastic vial and label with the patient's full name exactly as it appears on the test requisition. Be careful not to transfer any red cells to the transfer vial.
  8. Freeze the specimen as soon as possible.
  9. Package specimens as directed in the Directory of Services.
  10. Transport specimens on dry ice. Specimens must remain frozen in transit.

Whole blood

  1. Perform a routine venipuncture.
  2. Use the blood collection tube identified in the Directory of Services. The collection tube must be completely filled. This ensures that the proper ratio of blood to anticoagulant is achieved.
  3. Invert each collection tube gently after collection.
  4. Label each patient's specimen with the patient's full name exactly as it appears on the test requisition.
  5. Maintain the specimen at room temperature unless otherwise instructed in the Directory of Services. Never freeze whole blood specimens unless indicated.
  6. Package specimens as directed in the Directory of Services.

Urine specimens

Routine urine

  1. Have the patient collect urine.
  2. “First morning” specimens are the preferred specimen for most routine urine studies. To reduce contamination, specimens should be a clean-catch midstream sample.
  3. Ensure that specimen container lid is tightly closed.
  4. Label each patient's specimen with the patient's full name exactly as it appears on the test requisition.
  5. Maintain the specimen at room temperature unless otherwise instructed in the Directory of Services.
  6. If a frozen specimen is required, transfer an aliquot of the specimen to a clean plastic vial, label it with the patient's full name exactly as it appears on the test requisition, and freeze immediately.
  7. Package specimens as directed in the Directory of Services.

24-hour urine

  1. Obtain the appropriate 24-hour urine collection container containing the required preservative from MLHL.
  2. Have the patient collect urine.
  3. Label the collection container with the patient’s full name, exactly as it appears on the test requisition.
  4. Have the patient collect the specimen according to the directions.
  5. After collection, have the patient return the specimen collection container to your office.
  6. Ensure that specimen container lid is tightly closed.
  7. Mix the specimen completely and record the total volume on the test requisition.
  8. Transfer an aliquot of the specimen to the plastic container provided by MLHL.
  9. Label the aliquot container with the patient's full name exactly as it appears on the test requisition.
  10. Maintain the specimen at room temperature unless otherwise instructed in the Directory of Services.
  11. Package specimens as directed in the Directory of Services.

Stool specimens

  1. Obtain the appropriate collection container from MLHL.
  2. Instruct the patient in the proper stool collection procedure.
  3. Label the collection container with the patient's full name, exactly as it appears on the test requisition.
  4. Have the patient collect the specimen according to the directions.
  5. After collection, have the patient return the specimen collection container to your office.
  6. Mix the specimen completely.
  7. Transfer an aliquot of the specimen to the plastic container provided by MLHL if required.
  8. Label the aliquot container with the patient’s full name exactly as it appears on the test requisition.
  9. Maintain the specimen at room temperature unless otherwise instructed in the Directory of Services.
  10. Package specimens as directed in the Directory of Services.

Submitting a specimen to MLHL for testing

  1. Complete an MLHL test requisition for each patient. Please ensure that the requisition includes the patient's full name, pertinent insurance information, required ICD-9 coding and all requested testing.
  2. Collect patient specimens using the blood collection tube, culture media or urine preservative indicated in the Directory of Services.
  3. Immediately label each specimen with the patient's full name exactly as it appears on the test requisition.
  4. Process specimens according to directions provided.
  5. Place each patient’s specimen and test requisition in a single specimen bag. Do not combine different patients’ specimens in the same bag.
  6. Frozen specimens must have a separate test requisition and be placed in a separate specimen bag.
  7. Place all specimen bags in the MLHL drop box for pick-up by our courier service.

Specimens failing to meet labeling criteria will result in calls to your office for clarification and may be rejected. No testing will be performed when patient identity is in question. This results in inconvenience to both you and your patient and delays in result reporting. Specimens must include the patient's full name. Please consult MLHL Specimen Labeling Requirements.

Common reasons for specimen rejection or inaccurate results

MLHL makes every attempt to minimize the rejection of client specimens. Specimen rejection delays reporting of results and inconveniences both the patient and you, the client. In certain instances, due to technical reasons, specimen rejection is required. Common reasons for specimen rejection include:

  • Incorrect specimen type submitted for analysis
  • Failure to appropriately label submitted specimens with patient name
  • Incorrect preservative used in 24-hour urine
  • Incorrect or incomplete processing of the specimen prior to submission
  • Thawing of frozen specimens in transit
  • Unlabeled specimens for blood bank testing
  • Hemolysis
  • Lipemia or turbidity
  • Hyperbilirubinemia

Special testing—HIV

By law, it is the practice of MLHL to require informed written consent prior to the collection of specimens for HIV antibody testing. This consent must be secured from the patient before HIV-related testing is initiated, except as authorized by law. Current Pennsylvania state law requires that:

  • The laboratory will not process blood for HIV antibody testing in the absence of a fully authorized HIV consent form.
  • The physician or designee ordering the HIV test will provide pretest counseling to the patient. Information related to pretest counseling is noted directly on the HIV consent form.
  • The physician or designee ordering the test will provide the patient with the opportunity for face-to-face discussions concerning the test results, whether positive or negative.

MLHL will provide your practice with special forms to be used in documenting the patient's informed consent. These forms must be completed and submitted to the laboratory with all HIV testing requests. These forms are available upon request.