DISKUSI CRP 2

Kelompok B-8

Critical Appraisal

“Verification of the ProPneumo-1 assay for the simultaneous detection of Mycoplasma pneumoniae

and Chlamydophila pneumoniae in clinical respiratory specimens”

Are the results of this diagnostic study valid?

Was there an independent, blind comparison with a reference (“gold”) standard of diagnosis?

No

Was the diagnostic test evaluated in an appropriate spectrum of patients (like those in whom it would be used in practice)?

Yes

Was the reference standard applied regardless of the diagnostic test result? YesWas the test (or cluster of tests) validated in a second, independent group of patients?

Yes

VALIDITY

Are the valid results of this diagnostic study important?

C.pneumoniae

Reference Method Results Totals

Positive Negative

Pro Pneumo-1

result

Positive 14A

0b

14a+b

Negative 0c

43d

43c+d

Totals 14a+c

43b+d

58a+b+c+d

Sensitivity= a/(a+c)= 100%Specificity= d/(b+d)= 100%Likelihood ratio for a positive test result= LR+ = sens/(1-spec)= ~Likelihood ratio for a negative test result= LR - = (1-sens)/spec= ~Positive Predictive Value= a/(a+b) = 100%Negative Predictive Value= d/(c+d) = 100%Pre-test probability(prevalence)= (a+c)/(a+b+c+d) = 25%Pre-test odds= prevalence/(1-prevalence)= 0,333Post-test odds= pre-test odds LR= ~Post-test probability= post-test odds/(post-test odds +1)= 100%

IMPORTANCE

M.pneumoniae

Reference Method Results Totals

Positive Negative

Pro Pneumo-1

result

Positive 41a

1B

42a+b

Negative 0c

47D

47c+d

Totals 41a+c

48b+d

89a+b+c+d

Sensitivity= a/(a+c)= 100%Specificity= d/(b+d)= 98%Likelihood ratio for a positive test result= LR+= sens/(1-spec)= 48Likelihood ratio for a negative test result= LR -= (1-sens)/spec= ~Positive Predictive Value= a/(a+b)= 98%Negative Predictive Value= d/(c+d)= 100%Pre-test probability(prevalence)= (a+c)/(a+b+c+d) = 46%Pre-test odds= prevalence/(1-prevalence)= 0,851Post-test odds= pre-test odds LR= 40,848Post-test probability= post-test odds/(post-test odds +1)= 98%

Can you apply this valid, important evidence about a diagnostic test in caring for your patient?Is the diagnostic test available, affordable, accurate, and precise in your setting?

No Availablebut accurate and precise

Can you generate a clinically sensible estimate of your patient’s pre-test probability (from personal experience, prevalence statistics, practice databases, or primary studies)?Are the study patients similar to your own?Is it unlikely that the disease possibilities or probabilities have changed since the evidence was gathered?

Yes

Will the resulting post-test probabilities affect your management and help your patient?Could it move you across a test-treatment threshold?Would your patient be a willing partner in carrying it out?

YesWould the consequences of the test help your patient?

Yes

APPLICLABILITY

TERIMA KASIH

Pertanyaan

• B5: apakah yang menjadi gold standard???• Blind dan double blind, apa bedanya????• Berapa harga pemeriksaan Pro-pneumo I???• Alasan tabel kedua dan keempat dalam

perhitungan?? Karena pemeriksaan tersebut (reference method results) dilakukan setelah “discordance analysis”

• Single blind: salah satu tidak mengetahui kepentingan pemeriksaan

• Double blind: antara subjek dan pemeriksa sama-sama tidak mengetahui kepentingan pemeriksaan.

• Triple blind: subjek, pemeriksa, penganalisa data tidak mengetahui kepentingan pemeriksaan. (hanya supervisor yang mengetahui)