Clinitek Status plus HCG Testing

I had one false positive Clinitest hCG result.  The specimen was bloody.  I submitted a ticket with Siemens tech support and they said that bloody urine specimens should not be tested with the Clinitest hCG cartridge because a false positive could occur. Below is the response from Siemens.  I hope this helps.

Complaint Closure Summary:

Problem Statement: The customer stated possible false positive hCG result in 1 patient sample on the Clinitek Status+ SN 305155 while using cassettes from lot 092001. The initial result was questioned by the physician. The patient was retested by serum hCG using another unknown instrument and they received a negative result. QC passed. Sample appearance was bloody and turbid. The customer followed proper maintenance and technique. Urinalysis was also conducted for the patient and moderate blood, trace protein, and small leukocyte readings were reported. Instrument is operational.

Results:

Analyte: hCG   Units: N/A

Patient ID        Date                  Method  Reagent lot  Result               Considered Correct?

Patient-1         26-Mar-26       Status+ SN 305155      092001            Positive            No

Patient-1         26-Mar-26       Serum hCG                    N/A                  Negative          Yes

 

Investigation Summary: DCU evaluated this event and an issue with sample was identified. Customer stated that a bloody sample was used for testing. Per the IFU, Siemens recommends not to use bloody or highly colored samples. Siemens also recommends ensuring proper maintenance and technique is followed when running patient samples (per the IFU). The DCU reviewed the Certificate of Analysis for lot 092001and the product met and passed all specifications upon manufacturing release. Additionally, the issue as described on lot 092001 has not been flagged as a potential trend per statistical analysis. Because an issue with sample clarity was identified, an investigation will not proceed. If the issue reoccurs after using the correct sample type (per IFU), please escalate and set aside 10 cartridges of the impacted lot so it can be investigated right away. As always, Siemens recommends using the Status+ per the Operator’s Manual and “Do It Right”; chart to ensure that proper technique and maintenance is always performed. The customer is operational. No further action is required by DCU. Closing event.

I have not been informed of any.

Can you tell us which lot numbers you're seeing this on? Just want to keep a pro-active eye out. :)

Thank you, guys. I'm thinking it's temperature related.  It was very hot the last few weeks so I'm think that might be the cause, but who knows.

Yes, the Lot number was 092530  exp 8/2027

False positives can occur due to a variety of reasons that can be attributed to the status of the patient. Certain tumors, recent preganncy, bloody, other contaminants that are listed in the insert. if there are uncertanties then the alternative should be your core lab test like beta hcg blood test.