Unless the patient is suspected to have laryngeal TB, laryngeal swabs are not recommended for diagnosing pulmonary TB due to the following reasons:
1. Difficulty in proper collection.
2. The amount of material collected on the swab is limited.
3. Risk of sharps injury from broken glass containers.
Specimens in transport swabs are not acceptable.
Turbid and grossly bloody specimens may contain inhibitors or give rise to false-positives due to high background.
If critical, blood/bone marrow specimens should be sent in plain tubes. Specimens sent in heparin-containing containers, Myco-F-Lytic or on slides are not suitable.
The Quantiferon-Plus tubes may be obtained from Client & Specimen Management (CSM) as follows:
Complete the Division's "Media Request Form” (fill in under "other") and fax to CSM (63265436) a day before collecting the tubes. The fax should reach CSM on Mondays to Fridays, between 0800 to 1600 hrs.
Collect the requested items from CSM, Academia Level 8, the following day between 0900 to 1200 hrs.
Collect whole blood (1ml per tube, accepted range = 0.8-1.2 ml) in the Quantiferon-Plus tubes in correct order: Nil (grey cap with white ring), TB1 (green cap with white ring), TB2 (yellow cap with white ring) then Mitogen (Purple cap with a white ring).
The blood volume in each tube should be within the black marking on the side. The black marking indicates the 0.8 ml to 1.2 ml fill volume, and the prevacuumed tubes have been validated by the manufacturer for volumes ranging from 0.8 to 1.2 ml.
Use a butterfly needle or vacutainer system - using hypodermic syringes increases the risk of sharps injury. Purge the contents of the butterfly tubing with a plain tube first.
1. Label all 4 tubes with the patient’s particulars, taking care to avoid obscuring the area where the blood filling and the black volume marks can be observed.
2. Indicate on the tubes or request form the date and time of specimen collection. For CPOE orders, print the barcodes just prior to the collection.
To avoid overfilling -
1. Before specimen collection, allow the tubes to equilibrate to room temperature (17-25ºC).
2. Do not choose a limb that has an intravenous drip attached or force blood into the tubes with a syringe.
3. Remove the tourniquet once blood enters the first tube. Note that the tubes draw blood relatively slowly; keep the tube on the needle for 2-3 seconds once the tube appears to have completed filling.
4. If the level of blood in any tube is not close to or exceeds the indicator line, another blood sample should be obtained.
Post collection, mix the blood with the tube contents by shaking tubes 10 times, to ensure that the entire inner surface of the tubes are coated with blood. Foaming may be expected and this will not affect the result. The shaking should not be so hard as to disrupt the gel at the base of the tubes as this may cause aberrant results.
Transport the tubes at room temperature (22 +/- 5ºC) to CSM before 1630 hrs on the same day of blood collection. It is not necessary for them to be transported upright.
Specimens must be received at CTBL within 16 hours of sample collection on Mon-Fri between 8.30 am - 5.00 pm. They will not be accepted on Saturday, Sunday, eve of public holidays and on public holidays.
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