Tips Regarding Sample Collection

Tips Regarding Sample Collection

Prevention of Haemolysis

Allow alcohol on venipuncture site to dry before inserting needle into the vein.

A 21-gauge needle (dark green holder) is recommended for collection of blood using non-vacutainer tubes. There is a greater likelihood of haemolysis with smaller gauge needles.

During venipuncture for collection of blood using non-vacutainer tubes, the plunger of the syringe should be drawn back slowly and the blood should flow freely.

After venipuncture for collection of blood using non-vacutainer tubes, remove the needle before allocating blood into the blood tubes and expel blood gently into the correct collection container.

After collecting blood into the blood tube containing anticoagulant, immediately invert the capped blood tube gently for several times to allow blood mixing with anticoagulant thoroughly to prevent clotting. Do not shake the blood tubes vigorously as this may cause haemolysis. Refer to Types of Specimen Collection Containers for number of inversions required.


Collection of Urine for Urine Culture

Clean catch for Midstream Urine
Wash hands with soap and water
Female :
1. With the labia (skin folds) apart around the urinary opening , cleanse the area with soap and
water using a front to back motion.
2. Be careful not to touch the insides of the container.
3. Urinate a small amount into the toilet or bedpan.
4. The midportion (midstream) should be collected into the container, about ½ full.
5. Ensure the container is tightly sealed.
1. Retract foreskin (uncircumcised patient) and cleanse the head of the penis.
2. Urinate a small amount into the toilet or bedpan.
3. The midportion (midstream) should be collected into the container, about ½ full.
4. Ensure the container is tightly sealed.

Arrange for the urine sample to be sent to the laboratory as soon as possible.

Please refrigerate the specimen if you are unable to ensure that it can reach the laboratory
within 2 hours from the time it was collected. Refrigerated specimens are required to be
processed the next day.

Collection of 24-hour Urine

Test results for 24-hour urine analysis are based on the total volume in a 24-hour period. See below for a good collection regime.

Day 1: Patient is to empty bladder completely at a designated time (e.g. 8am). This specimen is discarded and the date and time are noted.

All subsequent voided urine is collected in a 24-hour urine container (obtainable from the laboratory) throughout the remaining of the day and night within the 24-hour period.

Day 2: Patient is to empty bladder at the same designated time on day 2 as noted on day 1 (e.g. 8am). This urine specimen is saved and collected together in the 24-hour urine container.

Stop the urine collection and label the 24-hour specimen container with patient’s name, NRIC (or Passport) number, date/time collection begins and date/time collection ends.

Normal fluid intake is encouraged during the 24-hour urine collection period. Dietary restrictions are required for some procedures. Please confirm with the laboratory.

Creatinine clearance test requires an estimate of body surface area. Thus patient’s height and weight must be indicated.


Collection of Specimen for Parasites

Stool Specimen

Stool specimens should not be contaminated with water or urine and remain at room temperature after collection in a clean or sterile container. When the specimen is to be examined for amoebae, arrange for it to be sent to the laboratory immediately.

Screening of parasites e.g. Malaria, Filaria, etc in blood and stool specimen

Examination of multiple specimens, e.g. 3 specimens, for the same patient during a period of 1 week may be necessary to coincide with the varying cyclical production of the diagnostic stages of the causative organism. Please indicate clearly the specimen number collected (e.g. specimen 1, specimen 2) and the date of specimen collection on the container and request form. For Inpatients, samples received after the third day of hospitalisation will not be accepted.

Collection of Arterial Blood for Blood Gas (Point-of-care test)

A 3 mL heparinized arterial blood collection syringe with rubber cap is recommended for collection of arterial sample for the determination of arterial blood gases.

After arterial blood collection, expel any air bubbles, mix the syringe gently and close the syringe with the rubber cap. Immediately test the sample (for bedside testing) or place in a sample biohazard bag, immerse the sample biohazard bag into “ice water” (do not place specimen directly in ice) and transport to the lab immediately (if it is to be tested in the laboratory).

The test MUST be performed within 10 minutes after collection.