In fact this problem is getting so bad that some laboratories are now refusing to process samples with inadequately completed request forms in order to try and force users to provide information. It is embarrassing to explain to your patient that you need to take a sample again as the laboratory rejected the previous sample because YOU didn’t fill out the form correctly!
What information is needed on a request form?
Microbiology forms have a number of sections on them and each needs filling in as accurately and comprehensively as possible. The sections are usually labelled:
- Patient’s details
- Requestor’s details
- Clinical information
- Test requested
Knowing this detail the lab staff can picture the “story”; the patient (heroine), the requestor (knight in shining armour), clinical details (the setting “in a land far away”, the baddy, a dragon or parasite) the test requested (the sword, the poisoned chalice, the additional test you can only perform once!)… oh dear, my imagination is getting away from me… back to the blog!
This includes information to identify the patient, and ensure that the right test is done on the right patient. The key pieces of information are name, date of birth, hospital number and NHS number. Without at least 3 patient identifiers the lab WILL NOT process the sample as there just won’t be any way of distinguishing who the result is for. For example a random search for say, “Sam Kettle” and you get a boxer, a pilot, an imprisoned football coach, a rugby player, a tri-athlete and even a female author! Which one are you talking about?
Some hospitals allow you to put patient stickers on the form but I am not really a fan of this even though it is quick and convenient. It is too easy to put the wrong sticker on the form and not notice. I have done this myself as a junior doctor; I needed to repeat the sample, apologise to the patient and label the forms correctly! On another occasion as a Microbiologist I was faced with the situation of having two patients with identical clinical stories, both with metallic heart valves, in beds next to each other on the same ward! I had a positive blood culture indicating infective endocarditis (a life threatening infection) but the name on the form didn’t match the name on the bottle (two different labels had been used)… it got worse as both were on antibiotics already and therefore the blood cultures couldn’t be repeated… what a nightmare just because of an admin error!
This is where the sample was taken e.g. Emergency Department, Intensive Care Unit, Ward 6 etc. as well as who the Consultant or General Practitioner is who has overall responsibility for the patient, PLUS who has taken the sample and requested the test PLUS a contact number in case there is a problem or the test result needs urgent action. It is also possible to add a “copy to” request so the lab can send an additional copy of the result to another healthcare professional; this is usually for complex patients where they may be more than one Consultant looking after the patient.
If this part of the request form isn’t completed then again many labs won’t process the sample. One particular reason why this is the case is that in the past unprofessional doctors have submitted their own samples and in extreme circumstances doctors have put patients at risk by sending in other peoples samples instead of their own in order to get around restrictions on their practice, both are against the General Medical Council code of contact. The main reason is so we can contact the person responsible for the patient and give them a timely result.
This is the biggest section on the form. The information for this section includes:
- Presenting complaint and provisional diagnosis
- Travel or contact with animals
- Other clinical conditions: pregnancy, cystic fibrosis, diabetes and other co-morbidities
- Kidney function
- Current, recent or planned treatment
- Any known antibiotic allergies
The presenting complaint, travel history, animal contact and other clinical conditions give the laboratory an idea of what the likely diagnosis is, as well as the type of microorganism that might be causing the infection. For example, a cough with productive sputum in someone with bronchiectasis indicates probable exacerbation of COPD (chronic obstructive pulmonary disease) so the lab will look for the common causes of exacerbation of COPD, whereas severe diarrhoea and sepsis in a patient who has returned from India might indicate possible enteric fever with typhoid or paratyphoid.
Other clinical conditions may also indicate a risk of opportunistic infections, for example if the patient has Cystic Fibrosis (CF) then Pseudomonas aeruginosa and Burkholderia spp. become significant pathogens; without knowing about the CF the lab won’t report or look for these bacteria in a patient’s sputum sample.
Clinical details also allow the lab to do the tests you should have asked for even if you forgot to ask for them! It’s often hard to remember the potential causes of a particular infection when you’re a tired doctor in the middle of the night or rushed off your feet without the time to add the detail... in these situations it’s often even difficult to remember your own name. So give yourself a break and give good clinical information; let the lab staff help you to do the right tests for your patients. If the lab gets no clinical information then at best they will only do the absolute minimum tests required which may not actually be what your patient needs or worse, the sample might be rejected.
While we’re talking about clinical details… writing “?UTI” on a urine request form is NOT adequate clinical details… it is just stating the blooming obvious… if the patient didn’t have an expected UTI then there would be no reason to send the urine sample in the first place! It would be better, for example, to say “dysuria, frequency, urgency, no catheter in situ, recent prostate biopsy” if these where the case!
It is important for the Microbiologist authorising the results to know what the patients kidney function is as well as what antibiotics have previously been given and which are going to be given, as well as any known allergies to antibiotics. This allows the Microbiologist to personalise the laboratory report to the patient. For example, if a patient has a UTI and has very poor renal function and a severe allergy to penicillin then the Microbiologist won’t just report out Trimethoprim, Nitrofurantoin and Amoxicillin as even though these are the first, second and third line treatments for UTI they are all contraindicated in THIS patient. Instead the Microbiologist might release Ciprofloxacin which is normally kept suppressed (to limit its use) but which would be appropriate for such a complex patient.
Clinical details also give the laboratory fair warning about any potentially harmful microorganisms that might be grown from the sample, as lab acquired infections can occur. You may not realise there is a risk, but by giving the lab the patient’s story you allow the lab to assess the risk for themselves.
I suspect that many requestors think this is the most important section on the request form, however hopefully you are now starting to realise this isn’t actually the case. In some respects the lab could cope without any test selection as the clinical details section should indicate what tests are required. The lab staff are highly trained professionals in their own right, the sample type with the clinical details are the most important factors for them to decide on the appropriate testing.
Now I’m not advocating leaving this blank (and I have seen someone write “you decide” on a form!) but it isn’t the end of the world if no test is requested. It is best practice to indicate the main tests required and then either the ward doctors or the lab staff can add further tests later if they are necessary. Use your differential diagnosis to inform your test selection and ask for tests for the life-threatening or common causes first. There is no need to look for every possible cause of an infection in every patient; be selective. A positive test for a rare cause is more likely to be a false positive than a true positive; tests are not 100% accurate. You might just have to take my word on this until I publish a future blog on the tricky concept of pre and post-test probability and interpreting likelihood ratios (OMG!!! it’s a tough one to get you head around, so be warned!)
So there you have it. Clinical details are the most essential part… By making sure your request forms are completed fully and accurately you’ll get a better microbiology service, try it and see the difference!
Now back to my storybook… there lived a dragon…, two fairies..., some elves…, and three giants... P.S. SPOILER: The knight in shining armour filled out the request form fully and the story has a happy ending.